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Number System - Quantitative Aptitude Questions with Answers

Questions
1 Find the Lowest Common Factor (LCM) of 18, 60
A 6
B 18
C 90
D 180

Answer: Option [D]

Quantitative Aptitude on LCM

The LCM of 18 and 60 is (2*3*3*10) = 180

2 Find the Highest Common Factor (HCF) of 18 and 60
A 6
B 9
C 20
D 30

Answer: Option [A]

Quantitative Aptitude on HCF

The HCF of 18 and 60 is (3*3) = 9

3 The product of two successive numbers is 8372. Which is the smaller between these two numbers?
A 75
B 64
C 91
D 82

Answer: Option [C]

Let the two numbers be x and (x+1) respectively

So, x(x+1) = 8372

x2 + x - 8372 = 0

x2 + 92x - 91x -8372 = 0

(x + 92)(x - 91) = 0

x = 91

Hence the two numbers are 92 and 91 and the smaller number is 91

4 The sum of four consecutive even numbers is 100. What is the sum of the squares of these numbers?
A 2430
B 2484
C 2520
D 2655

Answer: Option [C]

Let the four consecutive even numbers be (x-2), x, (x+2) and (x+4) respectively.

Then, (x-2)+x+(x+2)+(x+4) = 100

4x + 4 = 100

x = 24

Hence the numbers are 22, 24, 26 and 26

The sum of their squares

= 222 + 242 + 262 + 282

= 2520

5 A, B, C, D, E are five consecutive odd numbers. The sum of A and C is 30. What is the value of E?
A 21
B 23
C 25
D 27

Answer: Option [D]

Let the five consecutive odd numbers be (x-4), (x-2), x, (x+2), (x+4) respectively.

Now, (x-4) + x = 30

x = 17

Therefore the value of E is (17+4) = 21

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