A cylindrical vessel, without lid, has to be tin-coated on its both si

1.	A cylindrical vessel, without lid, has to be tin-coated on its both sides. If the radius of the base is 70 cm and its height is 1.4 m, calculate the cost of tin-coating at the rate of Rs. 3.50 per 1000 cm2.
Answer» We have, Radius of base = 70 cm Height of base = 1.4 m = 140 cm Rate of tin plating = Rs 3.50 per cm² So, Total surface area of vessel = Area of outer side of base + Area of inner and outer curved surface = 2 (πr² + 2 πrh) = 2πr (r + 2h) = 2 × 22/7 × 70 (70 + 2(140)) = 2 × 22/7 × 70 (350) = 154000 cm² ∴ Cost of tin coating at the rate of Rs 3.50 per 1000 cm² = 3.50/1000 × 154000 = Rs 539

A cylindrical vessel, without lid, has to be tin-coated on its both sides. If the radius of the base is 70 cm and its height is 1.4 m, calculate the cost of tin-coating at the rate of Rs. 3.50 per 1000 cm2.

Answer»

We have,

Radius of base = 70 cm

Height of base = 1.4 m = 140 cm

Rate of tin plating = Rs 3.50 per cm²

So,

Total surface area of vessel = Area of outer side of base + Area of inner and outer curved surface

= 2 (πr² + 2 πrh)

= 2πr (r + 2h)

= 2 × 22/7 × 70 (70 + 2(140))

= 2 × 22/7 × 70 (350)

= 154000 cm²

∴ Cost of tin coating at the rate of Rs 3.50 per 1000 cm² = 3.50/1000 × 154000

= Rs 539