Subject: General Aptitude · Chapter: Area · Exam: · Marks: · Difficulty:
If the breadth of a rectangle is decreased by 50\%, then to double the area, its length is required to be increased by
(a)150\%
(b)200\%
(c)300\%
(d)400\%
Answer
Answer (as printed): C
Explanation
Let the original length and breadth of the rectangle be $l$ and $b$ respectively Then, original area $=l b$. New area $=2 l b$. New breadth = 50\% of $b=\frac{b}{2}$. New length $=\frac{2 l b}{\left(\frac{b}{2}\right)}=4 l$. Increase in length $=(4 l-l)=3 l$. $$\text { ∴ Increase } \%=\left(3 l \times \frac{1}{l} \times 100\right) \%=300 \% \text {. }$$
Explanation as extracted from the printed page; notation may be imperfect.