Q30 of 47 Page 1

A container open at the tip, is in the 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 milk which can completely fill the container at the rate of ₹21 per litre. [Use π = 22/7

Volume of a frustum of a cone = πh (R2 + r2 + Rr)

where,


R = upper circular radius


r = lower circular radius


Volume of the cone =


=


=


= 15689.14 cm3


[Using the relation 1 cm3 = 0.001 l]


Volume (in litres) = 15.689 l


⸫ Cost of milk to fill the container = ₹21 × 15.689 l


= ₹329.47


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