A water well has a height of h meters and a diameter of 21 m. The cost of plastering the well is ₹1,36,125 at the rate of ₹275/m2, then find the height of the well. (π = )
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 7.5 m.
Radius (r) = 21/2 = 10.5 m
Surface area = 136125/275 = 495 m2
2πrh = 495
⇒ 2 × (22/7) × 10.5 × h = 495
⇒ h = 7.5 m