Aptitude - Numbers

Exercise : Numbers - General Questions
6.
How many of the following numbers are divisible by 132 ?
264, 396, 462, 792, 968, 2178, 5184, 6336
4
5
6
7
Answer: Option
Explanation:

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.


7.
(935421 x 625) = ?
575648125
584638125
584649125
585628125
Answer: Option
Explanation:

935421 x 625 = 935421 x 54 = 935421 x 10 4
2

= 935421 x 104 = 9354210000
24 16

= 584638125


8.
The largest 4 digit number exactly divisible by 88 is:
9944
9768
9988
8888
None of these
Answer: Option
Explanation:
Largest 4-digit number = 9999

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

9.
Which of the following is a prime number ?
33
81
93
97
Answer: Option
Explanation:
Clearly, 97 is a prime number.

10.
What is the unit digit in {(6374)1793 x (625)317 x (341491)}?
2
3
5
Answer: Option
Explanation:

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.