Arithmetic Aptitude

Question 1

(1015)² = ?

• A. 1040125
• B. 1030225
• C. 1050125
• D. 1025125

Answer: (B)

10152 = (1000+15)2
= 10002 + 152 +2 x 1000 x 15
=1000000 + 225 + 30000
=1030225

Question 2

Which one is NOT divisible by 3 ?

• A. 5271
• B. 6291
• C. 4372
• D. 8952

Answer: (C)

If the total of digits is divisible by 3, number is also divisible by 3. 5271……..5+2+7+1=15 is divisible by 3 6291……..6+2+9+1=18 is divisible by3 4372……..4+3+7+2=16 is not divisible by 3 8952……..8+9+5+2=24 is divisible by 3

Question 3

Largest five digit number exactly divisible by 39 is:

• A. 99979
• B. 99956
• C. 99989
• D. 99996

Answer: (D)

Largest 5 digit number is 99999.
Let us divide 99999 by 39

39) 99999 (2564
      78
      -----
      219
      195
      -----
        249
        234
        -----
           159
           156
           ----
              3

From above calculation, we know 39*2564 + 3 = 99999
Therefore 99999-3 = 99996 is the largest divisible number by 39.

Question 4

Which is not the prime number?

• A. 43
• B. 57
• C. 73
• D. 101

Answer: (B)

A positive natural number is called prime number if nothing divides it except the number itself and 1. 57 is not a prime number as it is divisible by 3 and 19.

Question 5

103 x 103 + 97 x 97 = ?

• A. 21348
• B. 20018
• C. 19648
• D. 21428

Answer: (B)

103 x 103 + 97 x 97
= (100+3)2 + (100-3)2
= 2 (1002 + 32 )  
[ (X +Y)2 + ( X – Y)2 = 2 ( X2 + Y2 ) ]
= 2 (10000 + 9 )
= 2 x 10009
= 20018

Question 6

9848 x 125 = ?

• A. 1232000
• B. 1242000
• C. 1231000
• D. 1233000

Answer: (C)

9848 x 125 = 9848 x (250 / 2)
           = 4924 x (500 / 2)
           = 2462 x (1000 / 2)
           = 1231 x (1000)
           = 1231000

Question 7

How many of the following numbers are divisible by 9 96381, 46729, 54459, 85369, 46818

• A. 1
• B. 2
• C. 4
• D. 3

Answer: (D)

If sum of digits are divisible by 9, number is also divisible by 9

96381…..9+6+3+8+1= 27    (/)
46729…..4+6+7+2+9= 28    (x)
54459…..5+4+4+5+9= 27    (/)
85369…..8+5+3+6+9= 31    (x)
46818…..4+6+8+1+8= 27    (/)

Question 8

What will be the next number? 3, 5, 7, 11, 13, 17…….

• A. 21
• B. 19
• C. 25
• D. 20

Answer: (B)

This is a sequence of prime numbers.

Question 9

P and Q can do a work in 30 and 60 days respectively. They agreed to work together and finish the work for 1000 Rupees. But they worked only for 10 days. How much money should they together get ?

• A. 500
• B. 100
• C. 800
• D. 200

Answer: (A)

one day combined work of P and Q= 1/30+1/60 = 1/20.
Thus P and Q can finish the work together in 20 days.
But they have worked only for 10 days which means they have finished half of the job.

So they will be paid half of the money= 500 rs

Question 10

If (4446)_x + (2222)_x = (10001)_x then value of (2342)_x - (1656)_x = (?)_x

• A. 453
• B. 353
• C. 893
• D. 686

Answer: (B)

in base 10 we know 6+2= 8 but in this question it is given 1 so we have to find the base of these numbers.
Now let the base be x so 6+2=8 -x= 1 thus base =7 (because in base 7, 8 will be represented as 1 carry and 1 addition ).
Now subtracting given numbers in base 7.