The area of a grassy plot is 480 sq. m. If each side had been 5 m longer, the area would have been increased by 245 sq. m. Find the length of the fence to surround it.

Answer: Option B

Let the length and breadth of the plot be l and b metres respectively
Then, lb = 480
And,
$$\begin{array}{rl}& \left(l+5\right)\left(b+5\right)=725\\ & \Rightarrow lb+5\left(l+b\right)+25=725\\ & \Rightarrow 5\left(l+b\right)+505=725\\ & \Rightarrow \left(l+b\right)=\frac{220}{5}\\ & \Rightarrow \left(l+b\right)=44\left[\because lb=480\right]\end{array}$$
∴ Length of the fence :
$$\begin{array}{rl}& =2\left(l+b\right)\\ & =\left(2\times 44\right)m\\ & =88m\end{array}$$