The total cost of flooring a room at Rs. 8.50 per square metre is Rs. 510. If the length of the room is 8 m, its breadth is :

Answer: Option A

Area of the floor :
$$\begin{array}{rl}& =\left(\frac{510}{8.50}\right)m^2\\ & =60m^2\end{array}$$
∴ Breadth of the room :
$$\begin{array}{rl}& =\left(\frac{60}{8}\right)m\\ & =7.5m\end{array}$$