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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.

Q 1 - 1000⁹ ÷ 10²⁶ = ?

Answer : C

Explanation

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

Q 2 - The sum of even numbers between 1 and 21 is?

Answer : A

Explanation

A.P -> a = 2, l = 20
-> a + (n - 1)d = 20
-> 2 + (n - 1) x 2 = 20
-> n = 10 i.e. terms = 10
S₂ = ⁿ⁄₂ (a + l)
= ¹⁰⁄₂ x (2 + 20)
= 110

Q 3 - Which of the following is a prime number?

Answer : A

Explanation

7 as it has no positive divisors except 1.

Q 4 - Which of the following numbers are divisible by 3 but not by 9?

Answer : C

Explanation

For this, calculate the sum of digits:
936: Sum of digits = 18 i.e. divisible by 3 and 9.
39987: Sum of digits = 36 i.e. divisible by 3 and 9.
2343: Sum of digits = 12 i.e. divisible by 3, but not by 9.
36: Sum of digits = 9 i.e. divisible by 3 and 9.

Q 5 - 190 x 5⁴ = ?

Answer : D

Explanation

= 190 x (¹⁰⁄₂)⁴
= ^{190 x 10⁴}⁄_2⁴
= 118750

Q 6 - Which of the following number divides 3²⁵ + 3²⁶ + 3²⁷ + 3²⁸ completely?

Answer : D

Explanation

  3²⁵ + 3²⁶ + 3²⁷ + 3²⁸  = 3²⁴ x (3¹ + 3² + 3³ + 3⁴)  = 3²⁴ x (3 + 9 + 27 + 81)  = 4⁶⁰ x 120  which is divisible by 30.

Q 7 - 1024 x 976 = y. What is y?

Answer : C

Explanation

  y =1024 x 976  = (1000 + 24) x (1000 - 24)  Now using formula (a+b)(a-b)=a²-b²  y = (1000)² - (24)²  = 1000000 - 576  = 999424

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

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^{= a^{2^{+ b^{2^{+ 2ab and  (a-b)^{2^{= a^{2^{+ b^{2^{- 2ab  (a+b)^{2^{+ (a-b)^{2^{= 2(a^{2^{+ b^{2^{)  ∴ y = 2 x [(200)^{2^{+ (17)^{2^{]  = 2 x [40000 + 289]  = 2 x 40289  = 80578}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}