Number System - Online Test

Q1. How many of the following numbers are divisible by 132 ? 264, 396, 462, 792, 968, 2178, 5184, 6336
Answer : Option A
Explaination / Solution:

132 = 4 x 3 x 11

So, if the number divisible by all the three number 4, 3 and 11, then the number is divisible by 132 also.

264  11,3,4 (/)

396  11,3,4 (/)

462  11,3 (X)

792  11,3,4 (/)

968  11,4 (X)

2178  11,3 (X)

5184  3,4 (X)

6336  11,3,4 (/)

Therefore the following numbers are divisible by 132 : 264, 396, 792 and 6336.

Required number of number = 4.


Q2. (935421 x 625) = ?
Answer : Option B
Explaination / Solution:

935421 x 625 = 935421 x 54 = 935421 x104
2

=935421 x 104=9354210000
2416

= 584638125


Q3. The largest 4 digit number exactly divisible by 88 is:
Answer : Option A
Explaination / Solution:

Largest 4-digit number = 9999

 88) 9999 (113
     88
     ----
     119
      88
     ----
      319
      264
      ---
       55
      ---
       
 Required number = (9999 - 55)
                 = 9944.

Q4. Which of the following is a prime number ?
Answer : Option D
Explaination / Solution:

Clearly, 97 is a prime number.

Q5. What is the unit digit in {(6374)1793 x (625)317 x (341491)}?
Answer : Option A
Explaination / Solution:

Unit digit in (6374)1793 = Unit digit in (4)1793

    = Unit digit in [(42)896 x 4]

    = Unit digit in (6 x 4) = 4

Unit digit in (625)317 = Unit digit in (5)317 = 5

Unit digit in (341)491 = Unit digit in (1)491 = 1

Required digit = Unit digit in (4 x 5 x 1) = 0.


Q6. 5358 x 51 = ?
Answer : Option A
Explaination / Solution:

5358 x 51= 5358 x (50 + 1)
= 5358 x 50 + 5358 x 1
= 267900 + 5358
= 273258.

Q7. The sum of first five prime numbers is:
Answer : Option D
Explaination / Solution:

Required sum = (2 + 3 + 5 + 7 + 11) = 28.

Note: 1 is not a prime number.


Q8. The difference of two numbers is 1365. On dividing the larger number by the smaller, we get 6 as quotient and the 15 as remainder. What is the smaller number ?
Answer : Option B
Explaination / Solution:

Let the smaller number be x. Then larger number = (x + 1365).

 x + 1365 = 6x + 15

 5x = 1350

 x = 270

Smaller number = 270.


Q9. (12)3 x 64 ÷ 432 = ?
Answer : Option A
Explaination / Solution:



Q10. 72519 x 9999 = ?
Answer : Option A
Explaination / Solution:

72519 x 9999= 72519 x (10000 - 1)
= 72519 x 10000 - 72519 x 1
= 725190000 - 72519
= 725117481.