A hemispherical bowl with a diameter of 14 cm has to be painted inside and outside. How much it will be charged at the rate of ₹20 per 40 cm2?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. ₹308.
Radius = 14 ÷ 2 = 7 cm
Total painted area = 2πr2 (inside) + 2πr2 (outside) = 4πr2
⇒ 4 × (22/7) × 7 × 7 = 4 × 154 = 616 cm2
Rate = ₹20 per 40 cm2 = ₹0.5 per cm2
Total cost = 616 × 0.5 = ₹308