Model Aptitude questions and answers for placement - Set 18

1)   How many 8's are present in the following sequence of numbers which are exactly divisible by both its preceding and following numbers ?

3 8 6 8 8 7 6 8 3 4 8 2 5 6 2 8 2 4 8 6 3 7 4 8 4 5 8 4


a. 5
b. 6
c. 2
d. Less than 4
e. None of these
Answer  Explanation 

ANSWER: Less than 4

Explanation:
3 8 6 8 8 7 6 8 3 4 8 2 5 6 2 8 2 4 8 6 3 7 4 8 4 5 8 4

We want a group of 3 numbers with “8” at the centre such that it would be exactly divisible by both its preceding and following numbers. There are 3 such groups. (See the underlined groups above).


2)   There are 30 people in a party. If everyone is to shake hands with one another, how many hand shakes are possible?

a. 180
b. 256
c. 386
d. 435
Answer  Explanation 

ANSWER: 435

Explanation:
Total number of persons = n = 30
Shakehands involve only 2 persons = r = 2
Number of shakehands = nCr = 30C2
30C2 = (30 * 29) /(2 * 1) = 435
nCr = (n!) / r! (n – r)!
= 30! / 2! 28!
= 435


3)   Two trains start at same time from two stations and proceed towards each other at the rate of 20 km/hr and 25 km/hr respectively. When they meet, it is found that one train has traveled 60 km more than the other. What is the distance between the two stations?

a. 620 km
b. 540 km
c. 460 km
d. 720 km
Answer  Explanation 

ANSWER: 540 km

Explanation:
Let us assume that trains meet after 'x' hours
Distance = speed * Time
Distance traveled by two trains = 20x km and 25x km resp.
As one train travels 60 km more than the other,
25x – 20x = 60
5x = 60
x = 12 hours
As the two trains are moving towards each other, relative speed = 20 + 25 = 45 km/hr
Therefore, total distance = 45*12 = 540 km.


4)   If Reena says, “Anjali's father Raman is the only son of my father-in-law Ramanand”, then how is Piyu, who is the sister of Anjali, related to Ramanand ?

a. Wife
b. Sister
c. Grand-daughter
d. Daughter
e. None of these
Answer  Explanation 

ANSWER: Grand-daughter

Explanation:
Only son of Reena's father-in-law Ramanand is Reena's husband. So, Raman is Reena's husband and Anjali & Piyu are his daughter's, Thus, Piyu is Grand-daughter of Ramanand.


5)   An article costs Rs. 600. What should be the marked price of an article so that after 10% discount, the trader makes 20% profit?

a. Rs. 800
b. Rs. 950
c. Rs. 1100
d. Rs. 1040
Answer  Explanation 

ANSWER: Rs. 800

Explanation:
Cost price of article = Rs. 600
Profit % = 20%
Therefore,
selling price of article = 120% of C.P.
= (120 / 100) * 600 = Rs. 720
Marked price = ?
Discount % = 10%
S.P. = Rs. 720
90% of M.P. = S.P.
90/100 * M.P. = 720
M.P. = 720 * (100/90) = Rs. 800


6)   A and B enter into a partnership with respective capitals of Rs. 20,000 and Rs. 40,000. At the end of the year, the total profit is Rs. 33,000. If A receives Rs. 15,000 as both his salary and profit, then what is his salary?

a. Rs. 2000
b. Rs. 4000
c. Rs. 3500
d. Rs. 3000
Answer  Explanation 

ANSWER: Rs. 4000

Explanation:
A's capital : B 's capital
20000 : 40000 = 1 : 2
Since, the time period is fixed, the profit is distributed in the ratio of capital 1 : 2
Profit of A = (1/3) * 33,000 = Rs. 11,000
Salary of A = Rs. (15000 – 11000) = Rs. 4000


7)   Find the principal which yields a simple interest of Rs. 20 and compound interest of Rs. 21 in two years, at the same percent rate per annum?

a. Rs. 520
b. Rs. 480
c. Rs. 420
d. Rs. 200
Answer  Explanation 

ANSWER: Rs. 200

Explanation:
SI in 2 years = Rs. 20, SI in 1 year = Rs. 10
CI in 2 years = Rs. 21
% rate per annum = [(CI – SI) / (SI in 1 year)] *100
= [(21 – 20) / 20] * 100
= 5 % p.a.

Let the principal be Rs. X
Time = T = 2 years
% rate = 5% p.a.
SI = (PRT/100)
20 = (X*5*2) / 100
X = Rs. 200


8)   If “*” is called “+”, “/” is called “*”, “-” is called “/”, “+” is called “-”. 40/20 – 5 * 10 + 5 = ?

a. 170
b. 160
c. 150
d. 175
e. None of these
Answer  Explanation 

ANSWER: None of these

Explanation:
Given : 40/20 – 5 * 10 + 5 = ?
Substituting the coded symbols for mathematical operations, we get,
40 * 20/5 +10 – 5 = ?
40 * 4 + 10 – 5 = ?
160 + 10 – 5 = ?
170 – 5 = 165


9)   The speed of boat in still water is 20 km/hr. If it travels 26 km downstream and 14 km upstream in same time, what is the speed of the stream?

a. 4 km/hr
b. 5 km/hr
c. 6 km/hr
d. 7 km/hr
Answer  Explanation 

ANSWER: 6 km/hr

Explanation:
Let X be speed of stream
Speed of boat downstream = (20 + X )
Speed of boat upstream = (20 – X)
It is given that boat takes same time to travel 26 km downstream and 14 km upstream
[26/(20 +X)] = [14 / (20 – X)]
520 – 26 X = 280 + 14X
40X = 240
X = 6 km/hr


10)   A traveler changes 150 pounds into rupees at the rate of Rs. 7000 for 100 pounds. He spends Rs. 9060 and changes the remaining amount back to pounds at the rate of 100 pounds to Rs. 7200. How many pounds will he get?

a. 18 pounds
b. 20 pounds
c. 25 pounds
d. 30 pounds
Answer  Explanation 

ANSWER: 20 pounds

Explanation:
Amount of rupees for exchange of 150 pounds = (150/100)*(7000/1) = Rs. 10,500
Out of these Rs.10,500, traveler spent Rs. 9060
Remaining balance in rupees = 10,500 – 9060 = Rs. 1440
Now these Rs. 1440 are exchanged back to pounds with the rate of 100 pounds for Rs. 7200
Amount in pounds = (1440 * 100) / 7200 = 20 pounds


11)   The average marks obtained by 100 candidates in an examination is 50. Find how many candidates have passed in the examination, if the average marks of candidates who passed is 70 and that of failed candidates is 20.

a. 90
b. 75
c. 60
d. 58
Answer  Explanation 

ANSWER: 60

Explanation:
Let the number of students who passed the examination be X
Number of students failed = (100 - X)
Total marks of students who have passed = 70X
Total marks of 100 students = 100 * 50 = 5000
Total marks of students who have failed = 20(100 – X)
20(100 – X) + 70X = 5000
2000 – 20 X + 70X = 5000
50 X = 3000
X = 60


12)   Find the missing number
Matrix form


a. 40
b. 38
c. 39
d. 35
e. None of these
Answer  Explanation 

ANSWER: 39

Explanation:
We have :
In first row, (5 * 6) – 2 = 30 – 2 = 28
In second row, (9 * 9) – 4 = 81 – 4 = 77
Thus,
In third row, the missing number is (7 * 6) – 3 = 42 – 3 = 39