A bucket, is in the form of frustum of a cone whose height is 42 cm and the radii of its circular ends are 30 cm and 10 cm. Find the amount of milk (in litres) which this bucket can hold. If the milkman sells the milk at the rate of Rs. 40 per litre. What amount he will get from the sale ? If the milkman sells half the milk at less rate to the economically weaker section of society, What value he exhibits by doing this ?
