Problems on Numbers - Quantitative Aptitude (MCQ) questions

1)   If the price of rice rises from Rs. 6 per kg to Rs. 8 per kg, to have no increase in his expenditure on rice, a person will have to reduce his consumption of sugar by
- Published on 05 May 16

a. 12 %
b. 19 %
c. 25 %
d. 32 %
Answer  Explanation 

ANSWER: 25 %

Explanation:
Let original consumption = 100 kg and consumption = y kg.
So, 100 x 6 = y x 8
y = 75 kg
Reduction in consumption = 25 %.


2)   The product of two numbers is 266 and their difference is 5. What is the bigger number ?
- Published on 25 Apr 16

a. 13
b. 15
c. 19
d. 24
e. None of these
Answer  Explanation 

ANSWER: 19

Explanation:
Let the two numbers be A and B, here A > B
AB = 266
B = 266/A -----------------(I)
Given,
A – B = 5 ----------- (II)
Substitute from (I) in (II), we get
A – 266/A = 5
A2 – 5A + 266 = 0
(A – 19)(A – 14) = 0
Therefore , A = 19 or A = 14
Hence, bigger number = A = 19


3)   What should come in place of the question mark (X) in the following equation ?
60% of X + 2/3 of 39 = 44

- Published on 22 Apr 16

a. 50
b. 60
c. 30
d. 20
e. None of these
Answer  Explanation 

ANSWER: 30

Explanation:
60% of X + 2/3 of 39 = 44
i.e. 3/5 of X + 2/3 of 39 = 44 (60% = 3/5)
3/5 * X + 2/3 * 39 = 44
3/5 * X + 26 = 44
3/5 * X = 18
X = 18 * 5/3
X = 30


4)   In a library, there are certain number of books on a shelf, ranging between 75 and 100. 1/6th of them are fiction and 12.5% of them are non-fiction. Find the number of books.
- Published on 20 Apr 16

a. 68
b. 72
c. 96
d. Can't be determined
e. None of these
Answer  Explanation 

ANSWER: 96

Explanation:
12.5% can be written as 1/8th
Since 1/6th of the books are fiction and 1/8th are non-fiction, the total number of books must be exactly divisible by 6 and 8 and should be between 75 and 100.
Therefore, 96 is the only number, which fulfills the above criteria.
Note that the question doesn't imply that there are ONLY two varieties of books.


5)   The incomes and expenditures of P, Q, R are in the ratio of 6 : 8 : 11 and 5 : 8 : 12 respectively. If P saves 1/4th of his income, what is the ratio of the savings of P, Q and R ?
- Published on 20 Apr 16

a. 15 : 8 : 2
b. 19 : 7 : 9
c. 7 : 15 : 10
d. 12 : 9 : 17
e. None of these
Answer  Explanation 

ANSWER: 15 : 8 : 2

Explanation:
Let the incomes of P, Q, R be 6x, 8x, 11x and expenditure be 5y, 8y and 12y respectively.
Therefore, savings are : (6x – 5y), (8x – 8y) and (11x – 12y)
Now, 6x – 5y = 1/4(6x)
24x – 20y = 6x
18x = 20y
x/y = 20/18 = 10 / 9
Savings of P / Savings of Q = 6x – 5y / 8x – 8y
= [6(x/y) – 5] / [8(x/y) – 8]
= [(6 * 10/9) – 5] / [(8 * 10/9) – 8]
= 15/8

Savings of Q / Savings of R = 8x – 8y / 11x – 12y
= [8(x/y) – 8] / [11(x/y) – 12]
= (8 * 10/9) – 8 / (11* 10/9) – 12
= 8/2
Ratio of savings of P : Q : R = 15 : 8 : 2


6)   What will come in place of the question mark (?) in the following question?

112.36 + 225.05 + ? = 815.30

- Published on 15 Apr 16

a. 474.46
b. 477.89
c. 524.41
d. 564.40
e. None of these
Answer  Explanation 

ANSWER: 477.89

Explanation:
815.30 - ( 112.36 + 225.05) = ?
= 477.89


7)   The product of two numbers is 168 and the sum of these two numbers is 26. What is the largest of these two numbers?
- Published on 13 Apr 16

a. 12
b. 14
c. 16
d. 18
e. None of these
Answer  Explanation 

ANSWER: 14

Explanation:
Let the numbers be x and (26 – x) .
Therefore,
x (26 – x) = 168
x2 – 26x + 168 = 0
(x – 14) (x – 12) = 0
x = 14 or x = 12
So, the numbers are 14 and 12.


8)   A number is doubled and 5 is added. If the resultant is trebled, it becomes 105. What is that number?
- Published on 12 Apr 16

a. 9
b. 15
c. 18
d. None of these
Answer  Explanation 

ANSWER: 15

Explanation:
Let the number be x.
Therefore,
3(2x + 5) = 105
6x + 15 = 105
6x = 90
x = 15


9)   If the sum of a number and its square is 272, What is the number?
- Published on 07 Apr 16

a. 14
b. 16
c. 19
d. 21
e. None of these
Answer  Explanation 

ANSWER: 16

Explanation:
Let the integer be x.
Then, x + x2 = 272
x2 + x - 272 = 0
(x + 17) (x – 16) = 0
x = 16


10)   For arranging a picnic, each student contributed an amount equal to the number of students while the teacher contributed an amount equal to twice the number of students. However, if each student would have contributed an amount equal to twice the number of students and the teacher would have contributed an amount equal to the number of students, they would have generated Rs. 1056 more. Find the number of students in the group?
- Published on 05 Apr 16

a. 24
b. 25
c. 33
d. 50
e. Cannot be determined
Answer  Explanation 

ANSWER: 33

Explanation:
Let the number of students = x. Thus, we get,
[(2x2 + x) – (x2 + 2x)] = 1056
x2 - x - 1056 = 0
Solving the equation, we get, x = 33 or x = - 32.
Since the number of students are to be positive, number of students = x = 33


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