# Maths GK Questions With Answers for Competitive Exams – Part 3

Maths Questions with answers for competitive exams is about GK questions of Mathematics for competitive exams. Here you can find out practice problems for competitive exams.

**MATHS QUESTIONS WITH ANSWERS FOR COMPETITIVE EXAMS – Part 3.**

- If 3/8 part of a number is 60, then find the number?
- Find the value of 1000 + 0.001?
- If we subtract 5 from twice a number, you will get 15, find the number?
- A: B = 2:3, B: C = 5:7 then A: C = ————–
- Find the cost of fencing a rectangular garden of length 100m and breadth 80m at the rate of Rs 25 per metre.
- Find the sum of all angles of a polygon of sides 15?
- Find the odd one out: 31, 41, 51,61.
- Find the difference between 10% of 50 and 12% of 100?
- Find the next number: 0.75, 2.25, 6.75, ————–
- HCF of two numbers is 6 and LCM is 144. If one number is 18, find the other number?

**ANSWERS WITH EXPLANATION:**

- 160

[Explanation: Let the number be x

Given 3/8 of x = 60

3x = 60 x 8

x = 480/3 = 160] - 1000.001
- 10

[Let the number be x

Given 2x – 5 = 15

2x = 15 + 5 = 20

x = 20/2 = 10] - 10:21

[Explanation: A/B = 2/3 X 5/5 = 10/15

B/C = 5/7 X 3/3 = 15/21

A/C = A/B X B/C = 10/15 X 15/21 = 10/21.

So A: C = 10: 21] - Rs 9000

[Explanation: Perimeter = 2 (l + b) = 2 (100 + 80) = 2 X 180 = 360m

Cost of fencing = 360 X 25 = 9000] - 2340 Degree

[Explanation: Sum of all angles of a polygon of n sides = (n – 2) 180

Here n = 15

Sum = (15 – 2) 180 = 13 X 180 = 2340 degree] - 51

[Explanation: 51 is a composite number, all other numbers given are prime numbers] - 7

[Explanation: 10% of 50 = 10 x 50/ 100 = 5

12% of 100 = 12 x 100/ 100 = 12

Difference = 12 – 5 = 7] - 20.25

[Explanation: 0.75 x 3 = 2.25

2.25 x 3 = 6.75

6.75 x 3 = 20.25] - 48

[Explanation: HCF x LCM = Product of 2 numbers

6 x 144 = 18x

x = 6 x 144/18 = 48.]