Question

A towel, when bleached, was found to have lost 20% of its length and 10% of its breadth. The percentage of decreases in area is
1. 10%
2. 10.08%
3. 20%
4. 28%

Answer 1

Correct Answer - Option 4 : 28%

Given:

The length of the towel is reduced by 20%

And the breadth of the towel is reduced by 10%.

Formula used:

Area of a rectangle = length × breadth

Percentage = (Part value/Whole value) × 100

Calculation:

Let the length be 10x cm

And the breadth be 10y cm

The area of the rectangle be

⇒ 10x × 10y = 100xy

After reduction the length is

⇒ 10x × (80/100) = 8x

⇒ 10y × (90/100) = 9

New area after reduction

⇒ 8x × 9y = 72xy

Change in area

⇒ 100xy - 72xy = 28xy

Change in Percentage

⇒ (28xy/100xy) × 100 = 28%

∴ Decreases in the area is 28%.