Question

The perimeter of rectangle is 240 cm. Ilits length is decreased by 10% and its breadth is increased by 20%we get the same perimeter. Find the length and breadth of the rectangle.​

Answer 1

Perimeter =240 cm
2(l+b) = 240
2l +2b =240 ..... (i)

$l \: is \: reduced \: by \: 10\% \: = \frac{10}{l} \times 100 \\ \: \: \: \: \: \: \: so \: \: \: \: \: new \: l \: = \frac{1000}{l} \\ b \: is \: increased \: by \: 20\% = \frac{20}{b} \times 100 \\ \: \: \: \: \: \: \: so \: \: \: \: \: new \: b \: \: = \frac{2000}{b}$