Subject: General Aptitude · Chapter: Area · Exam: 2008 · Marks: · Difficulty:
A towel, when bleached, was found to have lost 20\% of its length and 10\% of its breadth. The percentage of decrease in area is
(a)10\%
(b)10.08\%
(c)20\%
(d)28\%
Answer
Answer (as printed): D
Explanation
Let original length $=x$ and original breadth $=y$. Decrease in area $=x y-\left(\frac{80}{100} x \times \frac{90}{100} y\right)$ $=\left(x y-\frac{18}{25} x y\right)=\frac{7}{25} x y$. $\therefore \quad$ Decrease $\%=\left(\frac{7}{25} x y \times \frac{1}{x y} \times 100\right) \%=28 \%$.
Explanation as extracted from the printed page; notation may be imperfect.