Question 56

A circular grassy plot of land, 42 m in diameter, has a path 3.5 m wide running around it outside. The cost of gravelling the path at Rs 4 per square metre is

Solution

As per the given question,

The area of the outer path = Area of outer circle - Area of inner circle

$$\Rightarrow \pi r_{1}^{2} - \pi r_{2}^{2}$$

$$\Rightarrow \pi (24.5^{2} - 21^{2})$$

$$\Rightarrow \frac{22}{7} (600.25 - 441)$$

$$\Rightarrow \frac{22}{7} (159.25) = 500.5$$

The cost of gravelling the path at Rs 4 per square metre = $$500.5 \times 4 = 2002$$

Hence, option C is the correct answer.

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