Question

A boy is running around a rectangular park, whose sides are in the ratio of $4:3$, at the rate of $10$ metre per second, and completes a round in $42$ seconds. Calculate the area of the park.

Answer 1

Perimeter $=10\times 42=420metre$
$\therefore$ (length + breadth) $=210$ metres
Hence, divide it in the ratio of $4:3$, for calculating length and breadth.
Length $=210\times \frac{4}{7}=120m$
Breadth $=210\times \frac{3}{7}=90m$
$\therefore$ Grass in the park (Area) $=120\times 90=10800$ sq. m.