The length of a rectangle is increased by 60%. By what percent would the width have to be decreased to maintain the same area ?
Area, General Aptitude, Percentage, Ratio and Proportion, RRB ASSISTANT LOCO PILOT (Patna) 2013, Solved
The length of a rectangle is increased by 60%. By what percent would the width have to be decreased to maintain the same area ?
A37(1 / 2)%
B0.6
C0.75
DNone
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Correct answer is: \(37 \frac{1}{2} \%\)
Explanation:
Let original length = x and
original breadth = y.
Then, original area = xyNew length =\( \frac{160x}{100} = \frac{8x}{5}\).
Let new breadth = zThen. \(\frac{8x}{5} \times z = xy => z = \frac{5y}{8}\)
\therefore Decrease in breadth = \(\Big(\frac{3y}{8} \times \frac{1}{y} \times 100 \Big) \% = 37\frac{1}{2}\% \)
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