Aptitude - Number System Online Quiz


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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 - What is the result of the following?

 4 + 44 + 444 + 4.44 

A - 486.44

B - 444

C - 496.44

D - 44

Answer : C

Explanation

496.44

Q 2 - If the number 517 * 324 is completely divisible by 3, then the smallest whole number in place of * will be?

A - 0

B - 3

C - 1

D - 2

Answer : D

Explanation

For this:
= (5 + 1 + 7 + x + 3 + 2 +4)
= 22 + x
Now, 22 + x must be divisible by 3. So, for this x should be 2.
22 + 2 = 24 i.e. divisible by 3

Q 3 - On dividing a number by 5, we get remainder as 3. What will be the remainder when the square of this number is divided by 5?

A - 3

B - 0

C - 1

D - 4

Answer : D

Explanation

Let number be p
Dividing p by 5, we get k as quotient and remainder as 3
p = 5k + 3 ->
p2 = (5k + 3)2 p = (25k2 + 30k + 9)
p = 5 (5k2 + 6k + 1) + 4
Therefore, we get 4 as remainder on dividing p2 by 5.

Q 4 - 12 + 22 + 32 + ... + 202 = ?

A - 872

B - 3920

C - 2870

D - 767

Answer : C

Explanation

As 12 + 22 + 32 + ... + n2 = 16 n (n + 1)(2n + 1)
Here, n = 20 -> Sum = 16 x 20 x 21 x 41
= 2870

Q 5 - 22 + 42 + 62 + ... + 142 = ?

A - 260

B - 730

C - 460

D - 560

Answer : D

Explanation

= (1 x 2) + (2 x 2) + (2 x 3) + ... + (2 x 7)
= (22 x 12) + (22 x 22) + (22 x 32) + ... + (22 x 72)
= 22 x [ 12 + 22 + 32 + ... + 72 ]
= 4 x 140
= 560

Q 6 - What is the unit digit in 584 x 428 x 667 x 213 ?

A - 2

B - 3

C - 4

D - 5

Answer : A

Explanation

  Multiply unit digits of each number. Unit digit in 584 x 428 x 667 x 213 = Unit digit in 4 x 8 x 7 x 3. = Unit digit in 672. = 2.  

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 - 1506 x 1506 = y. What is y?

A - 2268016

B - 2268026

C - 2268046

D - 2268036

Answer : D

Explanation

  y = 1506 x 1506   = (1500 + 6) x (1500 + 6)  = (1500 + 6)2  Using formulae (a+b)2 = a2 + b2 + 2ab  ∴ y = (1500)2 + (6)2 + 2 x 1500 x 6  = 2250000 + 36 + 18000  = 2268036  

Q 9 - What is the largest number which can divide n3 - n for every natural number n?

A - 2

B - 3

C - 6

D - 12

Answer : A

Explanation

  (2)3 - 2 = 6   ∴ 6 is the largest number which can divide n3 - n for every natural number n.  

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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