Question

The length and breadth of a rectangular field in the ratio $4:3$. If its area is $300m^2$, then find the cost of fencing it @Rs $4$ per metre.

Answer 1

$\frac{length}{breadth}=\frac{4}{3}$

if length $=4x$

$breadth=4x\times \frac{3}{4}=3x$

$area=length\times breadth$

$300=\left(4x\right)\left(3x\right)$

$\Rightarrow$ $x^2=25\Rightarrow$ $x=5$

$\therefore$ length $20m$ and breadth $=3\left(5\right)=15cm$

Perimeter of rectangle $2(l+b))=2(15+20)70m$

Cost of $1m$ fence $=Rs.4$

Cost of $70m$ fence $=Rs.(4\times 10)=Rs.280$

It costs Rs. $280$ to fence the rectangular field