Q39 of 40 Page 1

A bucket is in the form of a frustum of a cone of height 16 cm with radii of its lower and upper circular ends as 8 cm and 20 cm respectively. Find the cost of milk which can completely fill the bucket, at the rate of ₹ 40 per litre. (Use π =3.14 )

r1 = 8cm , r2 = 200 cm, h = 16cm



Volume of bucket =




= 10,449.92 cm3


= 10,449.92 × 10-6 × m3


= 10,449.92 × 10-6 × 103 L


= 10, 449.92 × 10-3 L


= 10. 449 L


Now , Cost of filling the milk = Rs 40 /L


∴ Cost of filling 10.449 L of milk = 10.449 × 40


= Rs 417.96


= Rs 418 (approx.)


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