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.

Solution (By Examveda Team)

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