Question

What will be the cost to cementing the inner surface of a well which is 9m deep and 133 cm in diameter at the rate of Rs 100 per m²
1. Rs 3456
2. Rs 6745
3. Rs 3762
4. Rs 3672

Answer 1

Correct Answer - Option 3 : Rs 3762

Given

Height of well = 9 m

Diameter of well = 133 cm

Formula used

Curved surface area of well = 2πrh

Where r and h are radius and height respectively

1m = 100 cm

Calculation

Diameter = 133cm or 1.33 m

Radius = 133/2

Curved surface area of well = 2× (22/7) × (1.33/2) × 9

⇒ 37.62 m²

Cost of cementing the well = 37.62 × 100

⇒ Rs.3762

∴ Cost of cementing is Rs.3762