Question

Find the cost of polishing the top surface of a circular dining table of diameter 7 m, if the rate of polishing is ₹30 per square metre.

• A. ₹1115
• B. ₹1555
• C. ₹1150
• D. ₹1155

Answer 1

The correct option is D ₹1155

The diameter of the top surface of the table = 'd' = 7 m
Thus the radius of the circular table = $\frac{7}{2}$ = 3.5 m
The area of the surface of the circular dining table = $\pi r^2$
= $\frac{22}{7}\times 3.5\times 3.5$
= $38.5m^2$
The cost of polishing dining table = Area × Unit cost
= $38.5\times 30$
= ₹ 1155