Question

The length of a rectangular blackboard id three times its width. If the width is $1.5m$, Find its area . Also find the cost of painting the blackboard at the rate of $Rs5.50persq.m$

Answer 1

Given:Length$=3x$ and Breadth$=x$

Width$=1.5$m$=150$cm

Perimeter$=2(l+b)$

$\Rightarrow 150=2(3x+x)$

$\Rightarrow 150=8x$

$\Rightarrow x=\frac{150}{8}=18.7$

$\therefore$ Breadth is $18.7$m and length is $3x=3\times 18.7=56.1$m

$\therefore$Area of the black board$=18.7\times 56.1=1,049.07‬m^2$

Cost of painting per sq.m$=$Rs$5.50$

Cost of painting $1,049.07‬m^2=$Rs$1,049.07\times 5.50=$Rs.$5,769.885$