The cost of painting the total surface area of a 30 m high solid right circular cylinder at the rate of ₹25 per m2 is ₹18,425. What is the volume (in m3) of this cylinder [π = ]?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 1155.
Given:
Total cost of painting = Rs 18425
Height = 30 m
TSA of cylinder = 2πr(r + h) ---- (1)
Volume of cylinder = πr2h ----- (2)
CSA of cylinder = Total cost of painting/Rate of painting = 18425/25 = 737
Using equation (1), we get
⇒ 2 × (22/7) × r × (r + 30) = 737
⇒ 4r(r + 30) = 469
⇒ r = 3.5
Now using equation (2), we get
Volume of the cylinder = (22/7) × 3.52 × 30
⇒ 1155 m3