Question

The sides of a rectangle are in the ratio 7 : 5 and its perimeter is 96 cm. The length of the rectangle is
(a) 21 cm
(b) 28 cm
(c) 35 cm
(d) 14 cm

Answer 1

(b) 28 cm

Let the length and the breadth of the rectangle be 7x cm and 5x cm, respectively.
It is given that the perimeter of the rectangle is 96 cm.
Perimeter of the rectangle = 2(7x+5x) cm

$$\begin{gathered} \Rightarrow 2(7\mathrm{x}+5x)=96 \\ =2\left(12x\right)=96 \\ =24x=96 \\ \Rightarrow x=\frac{96}{24}=4 \\ \therefore \mathrm{Length}=(7\times 4)\mathrm{cm}=28\mathrm{cm} \end{gathered}$$