Question

A towel, when bleached, was found to have lost 20% of its length and 10%
its breadth. What is the percentage of decrease in the areaa?​

Answer 1

Let the length and breadth of the towel be”l” and “b”, then the area of the rectangle= lb.

If the length is reduced by 20% and breadth by 10% then the new length and breadth are 0.8 l and 0.9 then the area of the bleached towel is = 0.8l x0.9b= 0.72 lb.

So the decrease in the area

=lb-0.72lb= lb(1.00–0.72)= 0.28 lb. So the area of the towel is decreased by 28%