Q34 of 50 Page 1

A container open at the top, is in form of a frustum of a cone of height 24 cm with radii of its lower and upper circular ends as 8 cm and 20 cm respectively. Find the cost of the milk which can completely fill the container at the rate of ₹21 per litre. [Use π = 22/7]

Given height, h = 24 cm


Upper radius, R = 20 m


Lower radius, r = 8 cm


We know that volume of a frustum of a cone = 1/3 πh (R2 + r2 + Rr)


⇒ Volume of the container





We know that 1000cm3 = 1 L


⇒ Volume


Rate per litre = ₹21


⇒ Cost of the milk in the container


= 329.472


∴ Cost of the milk = ₹329. 47


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