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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 difference of the squares of two consecutive even integers is divisible by which of the following integers?

Answer : D

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 terms are there in the G.P 3, 6, 12, ... , 768?

Answer : B

Explanation

a = 3, r = ⁶⁄₂ = 2
Let number of terms = n
-> t_n = 768
-> 768 = ar^n-1
-> 768 = 3 x 2^n-1
-> ⁷⁶⁸⁄₃ = 2^n-1
-> 256 = 2^n-1
-> 2⁸ = 2^n-1
-> n = 9
Therefore number of terms = 9

Q 5 - If 653pq is divisible by 90, then (p + q) =?

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 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 - 14927 x 567 - 14927 x 467 = y. What is y?

Answer : B

Explanation

  y = 14927 x 567 - 14927 x 467   = 14927 x (567 - 467)   = 14927 x 100  = 1492700

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

Answer : A

Explanation

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

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