Aptitude - Number System Online Quiz



Following quiz provides Multiple Choice Questions (MCQs) related to Number System. You will have to read all the given answers and click over the correct answer. If you are not sure about the answer then you can check the answer using Show Answer button. You can use Next Quiz button to check new set of questions in the quiz.

Questions and Answers

Q 1 - The unit digit in the product (636 x 924 x 368)?

A - 5

B - 7

C - 2

D - 1

Answer : C

Explanation

Unit Digit = Unit Digit in (6 x 4 x 8) = 2

Q 2 - (568 x 568 x 568 + 432 x 432 x 432) / (568 x 568 - 568 x 432 + 432 + 432) = ?

A - 568

B - 1000

C - 432

D - 10

Answer : B

Explanation

This is solved using the following formulae:
(a3 + b3) = (a + b)( a2 - ab + b2)
The value of (a+b) =
(a3 + b3) / ( a2 - ab + b2) =
(568 + 432) = 1000

Q 3 - The difference of the squares of two consecutive even integers is divisible by which of the following integers?

A - 1

B - 5

C - 4

D - 2

Answer : C

Explanation

Let the consecutive integers(even) be 2p and (2p + 2):
= (2p + 2)2 - 2p2 = (2p + 2 + 2p)(2p + 2 -2p)
= 2(4p + 2)
= 4 (2p + 1)
Therefore, divisible by 4.

Q 4 - It is being given that (232) + 1) is completely divisible by a whole number. Which of the following numbers is completely divisible by this number?

A - 216 - 1

B - 216 + 1

C - 296 + 1

D - none of these

Answer : C

Explanation

Let 232 = p
-> (232 + 1) = p + 1
Let (p + 1) be completely divisible by natural number Z. Then->
(296 + 1) = [(232)3 + 1]
As (p3 + 1) = (p + 1)(p2 - p + 1), which is completely divisible by Z, since (p + 1) is completely divisible by Z.

Q 5 - I how many ways can 22500 be written as a product of two different factors?

A - 10

B - 32

C - 22

D - 12

Answer : C

Explanation

1502 = 22500
Therefore, 1502 = ((2)(5)(3)(5))2 = 225432
= 12{(2 + 1)(4 + 1)(2 + 1) - 1}
= 22

Q 6 - If unit digit in 549 x 56 x 28p x 684 is 8 then what is p?

A - 4

B - 3

C - 2

D - 1

Answer : B

Explanation

  Multiply unit digits of each number. Unit digit in 549 x 56 x 28p x 684 = 8 Unit digit in 9 x 6 x p x 4 = 8 Unit digit in 216 x p = 8 Thus p must be 3.  

Q 7 - 1014 x 986 = y. What is y?

A - 988804

B - 998814

C - 998904

D - 999804

Answer : D

Explanation

 y =1014 x 986 = 1014 x (1000 - 14) = 1014000 - 14196 = 999804  

Q 8 - 217 x 217 + 183 x 183 = y. What is y?

A - 79698

B - 80578

C - 80698

D - 81238

Answer : B

Explanation

  y = 217 x 217 + 183 x 183    = (217)2 + (183)2  = (200 + 17)2 + (200 -17)2  Using formulae (a+b)2 = a2 + b2 + 2ab and  (a-b)2 = a2 + b2 - 2ab  (a+b)2 + (a-b)2 = 2(a2 + b2)  ∴ y = 2 x [(200)2 + (17)2]  = 2 x [40000 + 289]  = 2 x 40289  = 80578  

Answer : A

Explanation

(a-b) divides an - bn completely for every natural number.

Q 10 - (6n2 + 6n) is always divisible by?

A - 6 only

B - 6 and 12 both

C - 18 only

D - 24 only

Answer : B

Explanation

  6n2 + 6n = 6(n)(n+1)  As n(n+1) is always even so number is divisible by 12 as well.  
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