Aptitude - Questions & Answers

Aptitude - Number System Online Quiz

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.

Q 1 - 1000⁹ ÷ 10²⁶ = ?

Answer : C

Explanation

= 1000⁹⁄_10²⁶
= (10³)⁹⁄_10²⁶
= 10²⁷⁄_10²⁶
= 10^{27 - 26}
= 10

Q 2 - Which of the following numbers is completely divisible by 45?

Answer : C

Explanation

45 = 5 x 9
So, co-primes are 5 and 9
For divisibility, the unit digits must be 0 or 5 and sum of digits must be divisible by 9.
The unit digit of 2025 is 5 and sum of digits is divisible by 9
Therefore, 2025 is completely divisible by 45.

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

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 - How many natural numbers are there between 17 and 9 which are exactly divisible by 6?

Answer : A

Explanation

Numbers -> 18, 24, 30, ... , 90
A.P: a = 18, d = 6, l = 90
t_n = a + (n-1)d
90 = 18 + (n-1)6
90 = 18 + 6n -6
n = 13

Q 5 - A number when divided by 296 leaves 75 as remainder. When the same number is divided by 37, the remainder will be?

Answer : C

Explanation

Lets x = 296q + 75 = (37 + 8q + 37 x 2) + 1
= 37 + (8q + 2) + 1
When the number is divided by 37, the remainder is 1.

Q 6 - What is the unit digit in in 3⁶⁵ x 6⁵⁹ x 7⁷¹ ?

Answer : C

Explanation

  3⁶⁵ = (3⁴)⁶ x 3 So Unit digit in 3⁶⁵ = Unit digit in 1 x 3 = 3  6⁵⁹ = (6⁴)¹⁴ x 6³ So Unit digit in 6⁵⁹ = Unit digit in 6 x 216 = 6  7⁷¹ = (7⁴)¹⁷ x 7³ So Unit digit in 7⁷¹ = Unit digit in 1 x 343 = 3  So Unit digit in 3⁶⁵ x 6⁵⁹ x 7⁷¹ = Unit digit in 3 x 6 x 3 = 4.

Q 7 - 935421 x 625 = y. What is y?

Answer : C

Explanation

  y = 935421 x 625  = 935421 x (5)⁴  = 935421 x (10/2)⁴  = (935421 x (10)⁴)/(2)⁴)  = 935421 x 10000 / 16  = 9354210000 / 16  = 584638125

Q 8 - 12846 x 593 + 12846 x 407 = y. What is y?

Answer : A

Explanation

  y = 12846 x 593 + 12846 x 407  = 12846 x (593 + 407)  = 12846 x 1000  = 12846000

Q 9 - a,b,c and d are consecutive odd number with average 42. What is the product of b and d?

Answer : C

Explanation

  let a = 2n + 1, b = 2n + 3, c = 2n + 5 and d = 2n + 7  Now (a + b + c + d) / 4 = 42  => (2n + 1 + 2n + 3 + 2n + 5 + 2n + 7) = 42 x 4  => 8n + 16 = 168  => n  = 152 / 8  => n = 19  ∴ b x d = (2 x 19 + 3) x (2 x 19 + 7)  = 41 x 45  = 1845

Q 10 - How many numbers are divisible by all 4,5 and 6 lying between 200 and 600.

Answer : B

Explanation

Each number should be divisible by L.C.M. of 4, 5 and 6 i.e. 60. So numbers are 240, 300, 360, 420, 480, 540. Count: 6

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