Question

The length of rectangle is increased by 10% and the breadth is increased by 25%. What is the percentage change in its area?

• A. Increase of 37.5%
• B. Decrease of 25%
• C. Decrease of 37.5%
• D. Increase of 25%

Answer 1

Answer:

A. Increase of 37.5%

Solution: Given: The length of the rectangle is increased by 10% Breadth is increased by 25% Concept Used: Area of rectangle = l × b Increase in percentage = [(changed% - initial%)/initial%] × 100 Calculation: Let the length and breadth of a rectangle is l and b An initial area of the rectangle = l × b Length increased by 10% = l + (10/100)l = (11/10)× l Breadth of rectangle increased by 25% = b + (25/100) × b= (5/4) × b New Increased area of rectangle = (11/10)× l × (5/4) × b = (11/8) × l × b Change in percentage of area = (11/8 - 1)/1 × 100 = (3/8) × 100 ⇒ 37.5% ∴ The area of the rectangle is increased by 37.5%