A container made up of a metal sheet is in the form of a frustum of a cone of height 16 cm with radii of its lower and upper ends as 8 cm and 20 cm respectively. Find the cost of the milk which can completely fill the container at the rate of ₹ 15 per litre. (Take π= 3·14)
100
R = 20 cm, r = 8cm, h = 16 cm
Volume of container =13πh{R2+r2+Rr}
= 13 × (3.14) × 16 { 400 + 64 + 160 } cm3
= 3.14 × 16 ×13 {624} cm3
= 3.14 × 16 × 208 cm3
= 10449.93 cm3
Therefore, the quantity of milk in the container = 10449.921000 liters = 10.45 liters
Cost of milk at the rate of ₹15 per liters = ₹ {10.45 × 15 } = ₹ 156.75