CDS Elementary Mathematics 2

Question 1

If the simple interest on $500 at 6% per annum for 3 years is calculated, what is the interest amount?

Accepted Answer

$90

Answer

Simple Interest = (P × R × T) / 100 = (500 × 6 × 3) / 100 = $90.

Question 2

What is the sum of interior angles of a hexagon?

Accepted Answer

720°

Answer

Sum of interior angles = (n − 2) × 180° = (6 − 2) × 180° = 720°.

Question 3

If 2x + 5 = 17, what is the value of x?

Accepted Answer

6

Answer

2x = 17 − 5 = 12, so x = 6.

Question 4

The average of five numbers is 24. If four of them are 18, 22, 28, and 30, what is the fifth number?

Accepted Answer

22

Answer

Total sum = 24 × 5 = 120; fifth number = 120 − (18+22+28+30) = 120 − 98 = 22.

Question 5

A circle has a radius of 7 cm. What is its circumference? (Use π = 22/7)

Accepted Answer

44 cm

Answer

Circumference = 2πr = 2 × (22/7) × 7 = 44 cm.

CDS - Combined Defence Services