Question

A hollow cyclinder pipe has inner circumference 44dm and outer 45dm. Find the cost of painting it from both sides at Rs 2 per m×m , if length is 3.5 m.

Answer 1

inner circumference = 44dm = 4.4m
outer circumference = 45dm = 4.5 m
length = 3.5m
inner CSA = 4.4×3.5 = 15.4 m²
outer CSA = 4.5×3.5 = 15.75 m²
total = 15.4 + 15.75 = 31.15 m²
cost = Rs. 2 per m²
total cost = 31.15×2 = Rs. 62.30