Question

The cost of fencing a circular plot at the rate of Rs.15 per m is Rs.3300. What will be the cost of flooring the plot at the rate of Rs.100 per sq m?

• A. Rs.385000
• B. Rs.220000
• C. Rs.350000
• D. Cannot be determined

Hint:

Find the radius from the fencing cost first, then use it to get the area.

Answer 1

The Correct Option is A

Step 1: Find the circumference first.
Fencing cost $= 15 \times$ circumference $= 3300$, so circumference $C = \frac{3300}{15} = 220$ m.

Step 2: Use the direct circumference to area shortcut instead of finding the radius separately.
Since $C = 2\pi r$, squaring gives $C^2 = 4\pi^2 r^2$, so the area $\pi r^2 = \frac{C^2}{4\pi}$. Substituting $C=220$ and $\pi = \frac{22}{7}$: area $= \frac{220^2}{4 \times \frac{22}{7}} = \frac{48400 \times 7}{88} = 3850$ sq m.

Final Answer:
Flooring cost $= 3850 \times 100 = 385000$, confirming option A. \[ \boxed{Rs.\,385000} \]