Question

Find the cost of painting the total outside surface area of solid cylinder 20m in height and 50cm in diameter at rupees 10.50 per 100 sq.m.

Answer 1

the answer is 2×22÷7×25÷20☺️

Answer 2

Cost of painting is ₹3.34

Given data :

Cylinder's height = 20m

Cylinder's diameter = 50 cm = 0.5 m

Painting cost = ₹ 10.50/100 m²

Cylinder's radius = 0.5/2 = 0.25 m

CSA of the cylinder = (2 × π × 0.25 × 20) = 31.42 m²

Top and bottom part area = {2× (π × 0.25 × 0.25)} = 0.39 m²

Total surface area = (31.42 + 0.39) = 31.81 m²

Now,

100 m² painting cost =₹ 10.50

1 m² painting cost = ₹ 10.50/100

31.81 m² painting cost = ₹ (10.50×31.81)/100 = ₹ 3.34 (answer)