Question

A towel, when bleached, was found to have lost 20% of its length and 10% of its breadth. The percentage decrease in area is:

• A. 10%
• B. 10.08%
• C. 20%
• D. 28%

Answer 1

The correct option is D 28%

Let original length = x and original breadth = y.
Decrease in area=xy-$(\frac{80x}{100}\times \frac{90y}{100})$
$=(xy-\frac{18}{25}xy)$
$=\frac{7}{25xy.}$
$\therefore$ %$=(\frac{7}{25}xy\times \frac{1}{xy}\times 100)$%=28%