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 - 20 + 15 X 3.5 = ?

A - 72

B - 72.5

C - 62.5

D - none of these

Answer : B

Explanation

= 20 + 15 x 3.5
= 20 + 15 x (7/2)
= 20 + 52.5
= 72.5

Q 2 - What is the unit digit of 1335

A - 1

B - 3

C - 4

D - 7

Answer : D

Explanation

131 has unit digit 3. 132 has unit digit 9. 133 has unit digit 7. 134 has unit digit 1. This will form a pattern 3-7-9-1. So 1332 has unit digit 1 and 1335 has unit digit as 7.

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 - If 653pq is divisible by 90, then (p + q) =?

A - 4

B - 7

C - 3

D - 9

Answer : A

Explanation

90 = 10 x 9
653pq is divisible by 10, so we can say that q = 0
Now,if 653p0 is divisible by 9.
So, (6 + 5 + 3 + p + 0) = (14 + p) is divisible by 9. So, p = 4.
Therefore, (p + q) = 4 + 0 = 4

Q 6 - What is the unit digit in 2137754 ?

A - 1

B - 3

C - 7

D - 9

Answer : D

Explanation

  unit digit in (2137)754 = unit digit in (7)754 = unit digit in (74)188 x 72 = unit digit in (1 x 49) = 9 Thus Unit digit in (2137)754 is 9.  

Q 7 - 916 x y x 3 = 214344. What is y?

A - 78

B - 68

C - 84

D - 66

Answer : A

Explanation

 916 x y x 3 = 214344 => 2748 x y = 214344 => y = 214344 / 2748 => y = 78  

Q 8 - 1008 x 992 = y. What is y?

A - 900936

B - 999816

C - 969836

D - 999836

Answer : A

Explanation

  y = 1008 x 992     = (1000 + 8) x (1000 - 8)  Using formulae (a+b)(a-b) = a2 - b2  ∴ y =  (1000)2 - (8)2  = 1000000 - 64  = 999936  

Q 9 - Which of the following will be an even number if a and b are odd numbers?

A - a + b

B - a + b + 1

C - ab

D - ab + 2

Answer : A

Explanation

Sum of two odd numbers is always even.

Q 10 - if a - b = 5 and a2 + b2 = 41, what is ab?

A - 5

B - 7

C - 8

D - 16

Answer : C

Explanation

  Using formulae (a-b)2 = a2 + b2 - 2ab  ab = (a2 + b2 - (a-b)2) / 2  => ab = [41 - (5)2] / 2  = 8  
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