The cost of painting the total outside surface of a closed cylindrical oil tank at 60 paise per sq. dm is Rs. 237.60. The height of the tank is 6 times the radius of the base of the tank. Find its volume correct to two decimal places.

Explanation

let the radius` = r dm`
then height` = 6r` dm volume of cylinder=`pi r^2 h= pir^2 xx 6 r`
the cost of painting the cylinder `60` paise per `dm^2` is given by `237.60`
i.e. volume` xx 0.6 = 237.60`
volume`= 237.60/0.6`
`= 396 dm^2`