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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 - What is the unit digit in (384)¹⁷⁹³ x (1035)³¹⁷ x (261)⁴⁹¹?

Answer : D

Explanation

Unit Digit in (384)¹⁷⁹³ = Unit Digit in (4)¹⁷⁹³ = Unit Digit in (4²)⁸⁹⁶ x 4 = Unit Digit in (6 x 4) = 4 Unit Digit in (1035)³¹⁷ = Unit Digit in (5)³¹⁷ = 5 Unit Digit in (261)⁴⁹¹ = Unit Digit in (1)⁴⁹¹ = 1 Therefore, unit digit in (384)¹⁷⁹³ x (1035)³¹⁷ x (261)⁴⁹¹ = Unit Digit in (4 x 5 x 1) = 0

Q 2 - Which of the numbers is exactly divisible by 3?

Answer : D

Explanation

Divisibility by 3: if sum of the digits is divisible by 3 then original number is divisible by 3. 413976, sum of digits is 30 thus the number is divisible by 3.

Q 3 - The smallest prime number is?

Answer : C

Explanation

The smallest prime number is 2.

Q 4 - When a number is divided by 17, the remainder is 9. When the same number is divided by 23, the remainder is 4. Find the number?

Answer : B

Explanation

x = 17p + 9 and x = 23q + 4
i.e. 17p + 9 = 23q + 4
Therefore, q = (17p + 5)/23
Least value of p for which q is a whole number is p = 20
x = 17p + 9
= 17 x 20 + 9
= 349

Q 5 - Find the total number of prime factors in the product (14)¹³ x 7³ x 9²?

Answer : D

Explanation

= (2 x 2)¹³ x 7³ x (3 x 3)³
= 2²⁶ x 7³ x 3⁴

Q 6 - Which of the following remains if 17²⁰⁰ is divided by 18?

Answer : C

Explanation

  As (a+b) always divides (aⁿ - bⁿ) if n is an even number.  ∴ 17²⁰⁰ - 1²⁰⁰ is divisible by 17 + 1  ∴ 17²⁰⁰ - 1 is divisible by 18  ∴ When 17²⁰⁰ is divided by 18, remainder is 1.

Q 7 - 496157 x 9999 = y. What is y?

Answer : B

Explanation

  y = 496157 x 9999    = 496157 x (10000 - 1)   = 496157 x 10000 - 496157   = 4961570000 - 496157   = 4691100843

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 - The sum of digits of two digit number is 10 and difference between the digits is 2. What is the number?

Answer : A

Explanation

  let number be ab  Thus a + b = 10 and a - b = 2  => (a + b) + (a - b) = 12  => 2a = 12  => a = 6  => b = 10 - a  = 10 - 6 = 4  ∴ number is 64.