Question

The perimeter of a rectangular playground is $84m$. If its length and breadth are in the ratio $5:2$ then the length of the ground is $m$.

• A. 30
• B. 12
• C. 20

Answer 1

The correct option is A 30

Perimeter of playground = $84m$...( Given)
Perimeter of rectangle $=2\left(\text{length + breadth}\right)$.

Since length and breadth are given to be in the ratio $5:2$, we can assume them to be $5x$ and $2x$ respectively.

i.e., length = $5x$ and breadth = $2x$

Substituting these in the formula of perimeter, we get
$84=2(5x+2x)\frac{84}{2}=(5x+2x)7x=42x=\frac{42}{7}x=6$

$\therefore$ Length of the ground
$=5x=5\times 6=30m$