Practice Verbal Reasoning questions on Series Completion, covering word and letter sequences, logical patterns, missing terms, alphabetical order, and identifying the rule that connects successive terms. Takes about 20-25 minutes and is useful for placement, TCS NQT, SSC, banking and MBA entrance exams.
Question 1
In the pattern below, each blank (_) stands for one missing letter. Choose the option that gives the missing letters, in order from left to right, so that the same block of letters repeats throughout.
a a b c b a a _ _ c b _ a a b c _ a
a a b c b a a _ _ c b _ a a b c _ a
Explanation
The pattern repeats the block 'aabcba' (6 letters) again and again. Written out in full the series is: a a b c b a a a b c b a a a b c b a. Reading the blanks from left to right gives a, b, a, b.
Question 2
In the pattern below, each blank (_) stands for one missing letter. Choose the option that gives the missing letters, in order from left to right, so that the same block of letters repeats throughout.
a b b c a _ _ b b _ a b a b _ c a b
a b b c a _ _ b b _ a b a b _ c a b
Explanation
The pattern repeats the block 'abbcab' (6 letters) again and again. Written out in full the series is: a b b c a b a b b c a b a b b c a b. Reading the blanks from left to right gives b, a, c, b.
Question 3
In the pattern below, each blank (_) stands for one missing letter. Choose the option that gives the missing letters, in order from left to right, so that the same block of letters repeats throughout.
b a c _ _ b _ a c c a _ b a c c a b
b a c _ _ b _ a c c a _ b a c c a b
Explanation
The pattern repeats the block 'baccab' (6 letters) again and again. Written out in full the series is: b a c c a b b a c c a b b a c c a b. Reading the blanks from left to right gives c, a, b, b.
Question 4
In the pattern below, each blank (_) stands for one missing letter. Choose the option that gives the missing letters, in order from left to right, so that the same block of letters repeats throughout.
c _ _ b a _ c a c b _ b c a c b a b
c _ _ b a _ c a c b _ b c a c b a b
Explanation
The pattern repeats the block 'cacbab' (6 letters) again and again. Written out in full the series is: c a c b a b c a c b a b c a c b a b. Reading the blanks from left to right gives a, c, b, a.
Question 5
In the pattern below, each blank (_) stands for one missing letter. Choose the option that gives the missing letters, in order from left to right, so that the same block of letters repeats throughout.
a c a b a a _ _ _ a _ c a b a
a c a b a a _ _ _ a _ c a b a
Explanation
The pattern repeats the block 'acaba' (5 letters) again and again. Written out in full the series is: a c a b a a c a b a a c a b a. Reading the blanks from left to right gives c, a, b, a.
Question 6
In the pattern below, each blank (_) stands for one missing letter. Choose the option that gives the missing letters, in order from left to right, so that the same block of letters repeats throughout.
c _ a a _ _ c a _ a c c a a a
c _ a a _ _ c a _ a c c a a a
Explanation
The pattern repeats the block 'ccaaa' (5 letters) again and again. Written out in full the series is: c c a a a c c a a a c c a a a. Reading the blanks from left to right gives c, a, c, a.
Question 7
In the pattern below, each blank (_) stands for one missing letter. Choose the option that gives the missing letters, in order from left to right, so that the same block of letters repeats throughout.
c b _ b _ c b b _ b c _ b b b
c b _ b _ c b b _ b c _ b b b
Explanation
The pattern repeats the block 'cbbbb' (5 letters) again and again. Written out in full the series is: c b b b b c b b b b c b b b b. Reading the blanks from left to right gives b, b, b, b.
Question 8
In the pattern below, each blank (_) stands for one missing letter. Choose the option that gives the missing letters, in order from left to right, so that the same block of letters repeats throughout.
c a _ a _ c a a a a _ a a _ a
c a _ a _ c a a a a _ a a _ a
Explanation
The pattern repeats the block 'caaaa' (5 letters) again and again. Written out in full the series is: c a a a a c a a a a c a a a a. Reading the blanks from left to right gives a, a, c, a.
Question 9
In the pattern below, each blank (_) stands for one missing letter. Choose the option that gives the missing letters, in order from left to right, so that the same block of letters repeats throughout.
c a _ b b c _ c b _ c a c _ b
c a _ b b c _ c b _ c a c _ b
Explanation
The pattern repeats the block 'cacbb' (5 letters) again and again. Written out in full the series is: c a c b b c a c b b c a c b b. Reading the blanks from left to right gives c, a, b, b.
Question 10
In the pattern below, each blank (_) stands for one missing letter. Choose the option that gives the missing letters, in order from left to right, so that the same block of letters repeats throughout.
a _ _ a a _ a c a a a a c a _
a _ _ a a _ a c a a a a c a _
Explanation
The pattern repeats the block 'aacaa' (5 letters) again and again. Written out in full the series is: a a c a a a a c a a a a c a a. Reading the blanks from left to right gives a, c, a, a.
Question 11
In the pattern below, each blank (_) stands for one missing letter. Choose the option that gives the missing letters, in order from left to right, so that the same block of letters repeats throughout.
b a _ c _ a c _ b _ c c
b a _ c _ a c _ b _ c c
Explanation
The pattern repeats the block 'bacc' (4 letters) again and again. Written out in full the series is: b a c c b a c c b a c c. Reading the blanks from left to right gives c, b, c, a.
Question 12
In the pattern below, each blank (_) stands for one missing letter. Choose the option that gives the missing letters, in order from left to right, so that the same block of letters repeats throughout.
b c _ a _ c b a b _ b _
b c _ a _ c b a b _ b _
Explanation
The pattern repeats the block 'bcba' (4 letters) again and again. Written out in full the series is: b c b a b c b a b c b a. Reading the blanks from left to right gives b, b, c, a.
Question 13
In the pattern below, each blank (_) stands for one missing letter. Choose the option that gives the missing letters, in order from left to right, so that the same block of letters repeats throughout.
b c c c b _ c c _ c _ _
b c c c b _ c c _ c _ _
Explanation
The pattern repeats the block 'bccc' (4 letters) again and again. Written out in full the series is: b c c c b c c c b c c c. Reading the blanks from left to right gives c, b, c, c.
Question 14
In the pattern below, each blank (_) stands for one missing letter. Choose the option that gives the missing letters, in order from left to right, so that the same block of letters repeats throughout.
c b a b c b _ b _ _ a _
c b a b c b _ b _ _ a _
Explanation
The pattern repeats the block 'cbab' (4 letters) again and again. Written out in full the series is: c b a b c b a b c b a b. Reading the blanks from left to right gives a, c, b, b.
Question 15
In the pattern below, each blank (_) stands for one missing letter. Choose the option that gives the missing letters, in order from left to right, so that the same block of letters repeats throughout.
b c a _ _ _ a a b c _ a
b c a _ _ _ a a b c _ a
Explanation
The pattern repeats the block 'bcaa' (4 letters) again and again. Written out in full the series is: b c a a b c a a b c a a. Reading the blanks from left to right gives a, b, c, a.
Question 16
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
CFI, DHL, EJO, ?
CFI, DHL, EJO, ?
Explanation
In each group the 1st letter moves 1 place, the 2nd letter 2 places and the 3rd letter 3 places forward from the same position in the previous group: CFI, DHL, EJO, FLR.
Question 17
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
AI, BJ, CK, ?
AI, BJ, CK, ?
Explanation
In every pair both letters move 1 place forward: AI, BJ, CK, DL.
Question 18
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
U, B, I, P, W, ?
U, B, I, P, W, ?
Explanation
Each letter is 7 places after the previous one, going round from Z to A: U, B, I, P, W, D.
Question 19
Choose the correct alternative that will continue the same pattern and replace the question marks in the given series.
Z, Y, X, U, T, S, P, O, N, K, ?, ?
Z, Y, X, U, T, S, P, O, N, K, ?, ?
Explanation
The series is made of reversed groups of three: ZYX, UTS, PON, KJI. Each group starts 5 places before the previous group.
Question 20
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
A, DE, HIJ, ?, STUVW
A, DE, HIJ, ?, STUVW
Explanation
Each group has one more consecutive letter than the one before (1, 2, 3, 4, 5 letters). The groups start at A, D, H, M, S (the starts move 3, 4, 5, 6 places). So the missing group is MNOP.
Question 21
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
BDF, HJL, NPR, ?
BDF, HJL, NPR, ?
Explanation
In each group the letters are 2 places apart, and each group starts 6 places after the previous start: BDF, HJL, NPR, TVX.
Question 22
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
EDUCATION, DUCATIO, UCATI, ?
EDUCATION, DUCATIO, UCATI, ?
Explanation
Each term is the previous one with its first and last letters removed: EDUCATION, DUCATIO, UCATI, CAT.
Question 23
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
B, D, F, I, L, P, ?
B, D, F, I, L, P, ?
Explanation
The jumps go +2, +2, +3, +3, +4, +4, so the next letter is P + 4 = T.
Question 24
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
P, Q, S, V, Z, ?
P, Q, S, V, Z, ?
Explanation
The jumps increase by one each time: +1, +2, +3, +4, +5. So the next letter is Z + 5 = E (going round from Z to A).
Question 25
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
Z, V, R, N, J, ?
Z, V, R, N, J, ?
Explanation
Each letter is 4 places before the previous one: Z, V, R, N, J, F.
Question 26
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
bgl, hmr, nsx, ?
bgl, hmr, nsx, ?
Explanation
Every letter moves 6 places forward, going round from Z to A: bgl, hmr, nsx, tyd.
Question 27
Choose the correct alternative that will continue the same pattern and replace the question marks in the given series.
Z, ?, T, ?, N, ?, H, ?
Z, ?, T, ?, N, ?, H, ?
Explanation
Each letter is 3 places before the previous one: Z, W, T, Q, N, K, H, E.
Question 28
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
TRANSACTION, RANSACTIO, ANSACTI, ?
TRANSACTION, RANSACTIO, ANSACTI, ?
Explanation
Each term is the previous one with its first and last letters removed: TRANSACTION, RANSACTIO, ANSACTI, NSACT.
Question 29
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
A, D, H, M, ?, Z
A, D, H, M, ?, Z
Explanation
The jumps increase by one each time: +3, +4, +5, +6, +7. So the missing letter is M + 6 = S, and S + 7 = Z.
Question 30
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
COMPUTER, OMPUTE, MPUT, ?
COMPUTER, OMPUTE, MPUT, ?
Explanation
Each term is the previous one with its first and last letters removed: COMPUTER, OMPUTE, MPUT, PU.
Question 31
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
AZ, CX, FU, ?, OL
AZ, CX, FU, ?, OL
Explanation
The 1st letters move 2, 3, 4, 5 places forward (A, C, F, J, O). The 2nd letters move 2, 3, 4, 5 places back (Z, X, U, Q, L). So the missing pair is JQ.
Question 32
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
BYD, DWG, FUJ, ?, JQP
BYD, DWG, FUJ, ?, JQP
Explanation
In each group the 1st letter moves 2 places forward, the 2nd letter moves 2 places back and the 3rd letter moves 3 places forward: BYD, DWG, FUJ, HSM, JQP.
Question 33
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
R, U, X, A, D, ?
R, U, X, A, D, ?
Explanation
Each letter is 3 places after the previous one, going round from Z to A: R, U, X, A, D, G.
Question 34
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
GH, JK, MN, PQ, ?
GH, JK, MN, PQ, ?
Explanation
Each pair moves 3 places forward: GH, JK, MN, PQ, ST.
Question 35
Choose the correct alternative that will continue the same pattern and replace the question marks in the given series.
A, B, M, C, D, N, E, F, O, ?, ?, ?
A, B, M, C, D, N, E, F, O, ?, ?, ?
Explanation
The series repeats in sets of three. The 1st and 2nd letters of each set continue the alphabet (A B, C D, E F, G H) and the 3rd letters are M, N, O, P (one place forward each time). So the missing letters are G, H, P.
Question 36
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
QNT, PMR, OLP, NKN, ?
QNT, PMR, OLP, NKN, ?
Explanation
In each group the 1st letter moves 1 place back, the 2nd letter moves 1 place back, and the 3rd letter moves 2 places back: QNT, PMR, OLP, NKN, MJL.
Question 37
Choose the correct alternative that will continue the same pattern and replace the question marks in the given series.
T, R, P, N, L, ?, ?
T, R, P, N, L, ?, ?
Explanation
Every letter is 2 places before the previous one: T, R, P, N, L, J, H.
Question 38
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
AZBYC, DXEWF, GVHUI, JTKSL, ?
AZBYC, DXEWF, GVHUI, JTKSL, ?
Explanation
In each group the 1st, 3rd and 5th letters run forward through the alphabet (A B C, D E F, G H I, J K L, M N O) and the 2nd and 4th letters run backward from the end (Z Y, X W, V U, T S, R Q). So the last group is M R N Q O.
Question 39
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
Z, X, U, Q, L, ?
Z, X, U, Q, L, ?
Explanation
The jumps back increase by one each time: 2, 3, 4, 5, 6. So the next letter is L - 6 = F.
Question 40
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
A, B, C, D, E, F, G, H, ?, J
A, B, C, D, E, F, G, H, ?, J
Explanation
The letters follow the alphabet in order, so the letter between H and J is I.
Question 41
Choose the correct alternative that will continue the same pattern and replace the question marks in the given series.
D, Y, G, W, J, U, M, ?, ?
D, Y, G, W, J, U, M, ?, ?
Explanation
Two series are interleaved. The 1st, 3rd, 5th, 7th and 9th letters are D, G, J, M, P (3 places forward each time). The 2nd, 4th, 6th and 8th letters are Y, W, U, S (2 places back each time). So the missing letters are S and P.
Question 42
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
Y, C, T, G, O, K, J, ?
Y, C, T, G, O, K, J, ?
Explanation
Two series are interleaved. The 1st, 3rd, 5th and 7th letters are Y, T, O, J (5 places back each time). The 2nd, 4th and 6th letters are C, G, K (4 places forward each time), so the 8th letter is K + 4 = O.
Question 43
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
AB, CDE, FGHI, ?, OPQRST
AB, CDE, FGHI, ?, OPQRST
Explanation
The groups use the alphabet in order and grow by one letter each time: AB (2), CDE (3), FGHI (4), JKLMN (5), OPQRST (6).
Question 44
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
beh, knq, ?
beh, knq, ?
Explanation
Every letter is 3 places after the one before it, continuing across the groups: b e h | k n q | t w z.
Question 45
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
B, H, M, Q, T, ?
B, H, M, Q, T, ?
Explanation
The jumps decrease by one each time: +6, +5, +4, +3, +2. So the next letter is T + 2 = V.
Question 46
Choose the correct alternative that will continue the same pattern and replace the question marks in the given series.
b, e, d, f, ?, h, j, m, ?
b, e, d, f, ?, h, j, m, ?
Explanation
Each group of three letters follows the same rule: first letter, then 3 places forward, then 1 place back from that. b-e-d, f-i-h, j-m-l. So the two missing letters are i and l.
Question 47
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
Z, V, W, R, T, N, Q, ?
Z, V, W, R, T, N, Q, ?
Explanation
Two series are interleaved. The 1st, 3rd, 5th and 7th letters are Z, W, T, Q (3 places back each time). The 2nd, 4th and 6th letters are V, R, N (4 places back each time), so the 8th letter is N - 4 = J.
Question 48
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
C, F, J, O, ?
C, F, J, O, ?
Explanation
The jumps increase by one each time: +3, +4, +5, +6. So the next letter is O + 6 = U.
Question 49
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
BD, FH, JL, ?, RT
BD, FH, JL, ?, RT
Explanation
In every pair both letters move 4 places forward: BD, FH, JL, NP, RT.
Question 50
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
X, U, R, O, ?
X, U, R, O, ?
Explanation
Each letter is 3 places before the previous one: X, U, R, O, L.
Question 51
Find the number that will replace the question mark (?) in the series.
15, 75, 145, 225, 315, ?
15, 75, 145, 225, 315, ?
Explanation
The differences are +60, +70, +80, +90, so the next difference is +100.
315 + 100 = 415.
315 + 100 = 415.
Question 52
Find the number that will replace the question mark (?) in the series.
4, 7, 19, 67, 259, ?
4, 7, 19, 67, 259, ?
Explanation
The differences are +3, +12, +48, +192, each 4 times the one before. The next difference is +768.
259 + 768 = 1027.
259 + 768 = 1027.
Question 53
Find the number that will replace the question mark (?) in the series.
13, 12, 121, 120, 1201, 1200, ?
13, 12, 121, 120, 1201, 1200, ?
Explanation
The operations alternate: -1, then ×10 + 1. 13 - 1 = 12, 12 × 10 + 1 = 121, 121 - 1 = 120, 120 × 10 + 1 = 1201, 1201 - 1 = 1200.
The next term is 1200 × 10 + 1 = 12001.
The next term is 1200 × 10 + 1 = 12001.
Question 54
Find the number that will replace the question mark (?) in the series.
20, 110, 210, 320, 440, ?
20, 110, 210, 320, 440, ?
Explanation
The differences are +90, +100, +110, +120, so the next difference is +130.
440 + 130 = 570.
440 + 130 = 570.
Question 55
Find the number that will replace the question mark (?) in the series.
1296, 6, 216, 36, 36, ?, 6
1296, 6, 216, 36, 36, ?, 6
Explanation
Two series are interwoven. Terms 1, 3, 5, 7: 1296, 216, 36, 6 (divided by 6 each time). Terms 2, 4, 6: 6, 36, 216 (multiplied by 6 each time).
The missing term is 216.
The missing term is 216.
Question 56
Find the number that will replace the question mark (?) in the series.
30, 54, 96, 162, 258, ?
30, 54, 96, 162, 258, ?
Explanation
The differences are 24, 42, 66, 96. These increase by 18, 24, 30, so the next increase is 36 and the next difference is 96 + 36 = 132.
258 + 132 = 390.
258 + 132 = 390.
Question 57
Find the number that will replace the question mark (?) in the series.
30, 28, 29, 25, 27, 23, 24, 22, ?
30, 28, 29, 25, 27, 23, 24, 22, ?
Explanation
Two series are interwoven. Terms 1, 3, 5, 7, 9: 30, 29, 27, 24, ? with differences -1, -2, -3, -4, so the missing term is 24 - 4 = 20.
Terms 2, 4, 6, 8: 28, 25, 23, 22 (differences -3, -2, -1).
Terms 2, 4, 6, 8: 28, 25, 23, 22 (differences -3, -2, -1).
Question 58
Find the number that will replace the question mark (?) in the series.
9, 21, 45, 81, ?
9, 21, 45, 81, ?
Explanation
The differences are +12, +24, +36, so the next difference is +48.
81 + 48 = 129.
81 + 48 = 129.
Question 59
Find the number that will replace the question mark (?) in the series.
3, 4, 10, 33, 136, ?
3, 4, 10, 33, 136, ?
Explanation
The operations are ×1 + 1, ×2 + 2, ×3 + 3, ×4 + 4, ×5 + 5: 3 × 1 + 1 = 4, 4 × 2 + 2 = 10, 10 × 3 + 3 = 33, 33 × 4 + 4 = 136.
The next term is 136 × 5 + 5 = 685.
The next term is 136 × 5 + 5 = 685.
Question 60
Find the number that will replace the question mark (?) in the series.
360, ?, 180, 60, 15, 3
360, ?, 180, 60, 15, 3
Explanation
Each term is divided by 1, 2, 3, 4, 5 in turn to give the next: 360 ÷ 1 = 360, 360 ÷ 2 = 180, 180 ÷ 3 = 60, 60 ÷ 4 = 15, 15 ÷ 5 = 3.
The missing term is 360.
The missing term is 360.
Question 61
Which of the following is a number in the series?
13, 21, 29, 37, 45, ...
13, 21, 29, 37, 45, ...
Explanation
The series increases by 8, so every term leaves remainder 5 when divided by 8.
517 = 8 × 64 + 5 belongs to the series. 246 and 574 leave remainder 6, and 1003 leaves remainder 3.
517 = 8 × 64 + 5 belongs to the series. 246 and 574 leave remainder 6, and 1003 leaves remainder 3.
Question 62
Find the number that will replace the question mark (?) in the series.
2, 6, 15, 31, 56, 92, ?
2, 6, 15, 31, 56, 92, ?
Explanation
The differences are +4, +9, +16, +25, +36, which are 22, 32, 42, 52, 62. The next difference is 72 = 49.
92 + 49 = 141.
92 + 49 = 141.
Question 63
Find the number that will replace the question mark (?) in the series.
6, 10, 18, 26, 38, ?
6, 10, 18, 26, 38, ?
Explanation
The differences are +4, then +8 twice, then +12 twice: 6 → 10 (+4), 18 (+8), 26 (+8), 38 (+12).
The next difference is the second +12, so 38 + 12 = 50.
The next difference is the second +12, so 38 + 12 = 50.
Question 64
Find the number that will replace the question mark (?) in the series.
3, 3, 6, 14, 29, ?
3, 3, 6, 14, 29, ?
Explanation
The differences are 0, 3, 8, 15, which are 12 - 1, 22 - 1, 32 - 1, 42 - 1. The next difference is 52 - 1 = 24.
29 + 24 = 53.
29 + 24 = 53.
Question 65
Find the number that will replace the question mark (?) in the series.
9, 25, 49, 81, 121, ?
9, 25, 49, 81, 121, ?
Explanation
The terms are squares of consecutive odd numbers: 32, 52, 72, 92, 112, 132.
132 = 169.
132 = 169.
Question 66
Find the number that will replace the question mark (?) in the series.
31, 38, 35, 42, 39, ?
31, 38, 35, 42, 39, ?
Explanation
The operations alternate: +7, -3, +7, -3, +7.
39 + 7 = 46.
39 + 7 = 46.
Question 67
What will be the 18th term of the series?
7, 13, 19, 25, ...
7, 13, 19, 25, ...
Explanation
This is an arithmetic progression with first term 7 and common difference 6.
The 18th term is 7 + 17 × 6 = 109.
The 18th term is 7 + 17 × 6 = 109.
Question 68
Find the number that will replace the question mark (?) in the series.
96, 54, 20, ?
96, 54, 20, ?
Explanation
Each term is the product of the digits of the previous term: 9 × 6 = 54, 5 × 4 = 20, 2 × 0 = 0.
Question 69
Find the number that will replace the question mark (?) in the series.
4, 9, 19, 39, 79, ?
4, 9, 19, 39, 79, ?
Explanation
Each term is double the previous term plus 1: 4 × 2 + 1 = 9, 9 × 2 + 1 = 19, 19 × 2 + 1 = 39, 39 × 2 + 1 = 79.
The next term is 79 × 2 + 1 = 159.
The next term is 79 × 2 + 1 = 159.
Question 70
Find the number that will replace the question mark (?) in the series.
17, 39, 511, 713, 915, ?
17, 39, 511, 713, 915, ?
Explanation
Each term joins two numbers: 1 and 7, 3 and 9, 5 and 11, 7 and 13, 9 and 15.
The next pair is 11 and 17, giving 1117.
The next pair is 11 and 17, giving 1117.
Question 71
Find the number that will replace the question mark (?) in the series.
400, 490, 310, 670, ?
400, 490, 310, 670, ?
Explanation
The differences are +90, -180, +360, each -2 times the one before. The next difference is -720.
670 - 720 = -50.
670 - 720 = -50.
Question 72
Find the number that will replace the question mark (?) in the series.
7, 13, 25, 43, 67, ?
7, 13, 25, 43, 67, ?
Explanation
The differences are +6, +12, +18, +24, so the next difference is +30.
67 + 30 = 97.
67 + 30 = 97.
Question 73
Find the number that will replace the question mark (?) in the series.
3, 17, 45, 87, 143, ?
3, 17, 45, 87, 143, ?
Explanation
The differences are +14, +28, +42, +56, so the next difference is +70.
143 + 70 = 213.
143 + 70 = 213.
Question 74
Find the number that will replace the question mark (?) in the series.
64, 32, 128, 64, 256, ?
64, 32, 128, 64, 256, ?
Explanation
The operations alternate: ÷2, ×4, ÷2, ×4, ÷2.
256 ÷ 2 = 128.
256 ÷ 2 = 128.
Question 75
Find the number that will replace the question mark (?) in the series.
72, 6, 12, 20, 30, 42, ?, 2, 3, 4, 5, 6, 7, 8, 9
72, 6, 12, 20, 30, 42, ?, 2, 3, 4, 5, 6, 7, 8, 9
Explanation
Each term before the question mark is the product of two consecutive numbers from the list that follows: 72 = 8 × 9, 6 = 2 × 3, 12 = 3 × 4, 20 = 4 × 5, 30 = 5 × 6, 42 = 6 × 7.
The missing term is 7 × 8 = 56.
The missing term is 7 × 8 = 56.
Question 76
Find the number that will replace the question mark (?) in the series.
3, 15, 35, ?, 99, 143
3, 15, 35, ?, 99, 143
Explanation
Each term is one less than a square of consecutive even numbers: 22 - 1 = 3, 42 - 1 = 15, 62 - 1 = 35, 82 - 1 = 63, 102 - 1 = 99, 122 - 1 = 143.
Question 77
Find the number that will replace the question mark (?) in the series.
11, 13, 17, 25, 41, ?
11, 13, 17, 25, 41, ?
Explanation
The differences are +2, +4, +8, +16, doubling each time. The next difference is +32.
41 + 32 = 73.
41 + 32 = 73.
Question 78
Find the number that will replace the question mark (?) in the series.
14, 27, 25, 38, 36, ?, 47, 60
14, 27, 25, 38, 36, ?, 47, 60
Explanation
Two series are interwoven. Terms 1, 3, 5, 7: 14, 25, 36, 47 (+11). Terms 2, 4, 6, 8: 27, 38, 49, 60 (+11).
The missing term is 49.
The missing term is 49.
Question 79
Which of the following numbers does not belong to the series of cubes?
Explanation
216 = 63, 343 = 73 and 512 = 83 are cubes. 650 lies between 83 = 512 and 93 = 729, so it is not a cube and does not belong to the series.
Question 80
Find the number that will replace the question mark (?) in the series.
3, 5, 8, 7, 10, 14, 11, 15, 20, ?
3, 5, 8, 7, 10, 14, 11, 15, 20, ?
Explanation
Three series are interwoven. Terms 1, 4, 7, 10: 3, 7, 11, 15 (+4). Terms 2, 5, 8: 5, 10, 15 (+5). Terms 3, 6, 9: 8, 14, 20 (+6).
The missing 10th term is 15.
The missing 10th term is 15.
Question 81
Find the number that will replace the question mark (?) in the series.
7, 21, 25, 125, 131, 917, ?
7, 21, 25, 125, 131, 917, ?
Explanation
The operations alternate and grow: ×3, +4, ×5, +6, ×7, +8.
917 + 8 = 925.
917 + 8 = 925.
Question 82
Find the number that will replace the question mark (?) in the series.
3, 8, 14, 21, 29, ?
3, 8, 14, 21, 29, ?
Explanation
The differences are +5, +6, +7, +8, so the next difference is +9.
29 + 9 = 38.
29 + 9 = 38.
Question 83
Which term of the series is 1701?
7, 21, 63, 189, 567, 1701, ...
7, 21, 63, 189, 567, 1701, ...
Explanation
Each term is 3 times the previous term: 7, 21, 63, 189, 567, 1701.
So 1701 is the 6th term.
So 1701 is the 6th term.
Question 84
Find the number that will replace the question mark (?) in the series.
7, 13, 22, 34, ?, 67
7, 13, 22, 34, ?, 67
Explanation
The differences are +6, +9, +12, +15, +18, each 3 more than the one before.
34 + 15 = 49, and 49 + 18 = 67, which matches the last term.
34 + 15 = 49, and 49 + 18 = 67, which matches the last term.
Question 85
Find the number that will replace the question mark (?) in the series.
5, 7, 11, 13, 17, ?, 23
5, 7, 11, 13, 17, ?, 23
Explanation
The terms are consecutive prime numbers: 5, 7, 11, 13, 17, 19, 23.
The missing term is 19.
The missing term is 19.
Question 86
Find the number that will replace the question mark (?) in the series.
300, 296, 287, 271, 246, ?
300, 296, 287, 271, 246, ?
Explanation
Consecutive squares are subtracted: 300 - 22 = 296, 296 - 32 = 287, 287 - 42 = 271, 271 - 52 = 246.
The next term is 246 - 62 = 210.
The next term is 246 - 62 = 210.
Question 87
Find the number that will replace the question mark (?) in the series.
5, 8, 11, 14, 19, 20, 29, 26, 41, 32, ?
5, 8, 11, 14, 19, 20, 29, 26, 41, 32, ?
Explanation
Two series are interwoven. The terms at odd positions are 5, 11, 19, 29, 41, ... with differences 6, 8, 10, 12, 14, so the next one is 41 + 14 = 55.
The terms at even positions are 8, 14, 20, 26, 32, which increase by 6.
The terms at even positions are 8, 14, 20, 26, 32, which increase by 6.
Question 88
Find the number that will replace the question mark (?) in the series.
1, 2, 3, 6, 11, 20, ?
1, 2, 3, 6, 11, 20, ?
Explanation
Each term from the fourth onwards is the sum of the previous three terms: 1 + 2 + 3 = 6, 2 + 3 + 6 = 11, 3 + 6 + 11 = 20.
The next term is 6 + 11 + 20 = 37.
The next term is 6 + 11 + 20 = 37.
Question 89
Find the number that will replace the question mark (?) in the series.
5, 6, 9, 15, 25, ?
5, 6, 9, 15, 25, ?
Explanation
The differences are +1, +3, +6, +10, which are consecutive triangular numbers. The next difference is +15.
25 + 15 = 40.
25 + 15 = 40.
Question 90
Find the number that will replace the question mark (?) in the series.
8, 17, 33, 67, 133, ?
8, 17, 33, 67, 133, ?
Explanation
Each term is doubled and then 1 is added and subtracted alternately: 8 × 2 + 1 = 17, 17 × 2 - 1 = 33, 33 × 2 + 1 = 67, 67 × 2 - 1 = 133.
The next term is 133 × 2 + 1 = 267.
The next term is 133 × 2 + 1 = 267.
Question 91
Find the number that will replace the question mark (?) in the series.
2, 4, 6, 12, 18, 36, ?
2, 4, 6, 12, 18, 36, ?
Explanation
The terms are multiplied alternately by 2 and 1.5: 2 × 2 = 4, 4 × 1.5 = 6, 6 × 2 = 12, 12 × 1.5 = 18, 18 × 2 = 36.
The next term is 36 × 1.5 = 54.
The next term is 36 × 1.5 = 54.
Question 92
Find the number that will replace the question mark (?) in the series.
1, 1, 4, 8, 9, 27, 16, ?
1, 1, 4, 8, 9, 27, 16, ?
Explanation
The terms alternate between squares and cubes: 12, 13, 22, 23, 32, 33, 42, 43.
The missing term is 43 = 64.
The missing term is 43 = 64.
Question 93
Find the number that will replace the question mark (?) in the series.
125, 80, 45, 20, ?
125, 80, 45, 20, ?
Explanation
The differences are -45, -35, -25, so the next difference is -15.
20 - 15 = 5.
20 - 15 = 5.
Question 94
What will be the 8th term of the series?
3, 9, 27, 81, ...
3, 9, 27, 81, ...
Explanation
Each term is multiplied by 3, so the nth term is 3n.
The 8th term is 38 = 6561.
The 8th term is 38 = 6561.
Question 95
Find the number that will replace the question mark (?) in the series.
4, 17, 290, ?
4, 17, 290, ?
Explanation
Each term is the square of the previous term plus 1: 42 + 1 = 17 and 172 + 1 = 290.
So the next term is 2902 + 1 = 84101.
So the next term is 2902 + 1 = 84101.
Question 96
Find the number that will replace the question mark (?) in the series.
746295831, 46295831, 4629583, 629583, ?
746295831, 46295831, 4629583, 629583, ?
Explanation
The digits are removed alternately from the beginning and from the end: first digit, last digit, first digit, then last digit.
746295831 → 46295831 → 4629583 → 629583 → 62958.
746295831 → 46295831 → 4629583 → 629583 → 62958.
Question 97
Find the number that will replace the question mark (?) in the series.
150, 127, 106, 87, 70, ?
150, 127, 106, 87, 70, ?
Explanation
The differences are -23, -21, -19, -17, so the next difference is -15.
70 - 15 = 55.
70 - 15 = 55.
