Question

A storage tank consists of a circular cylinder with a hemisphere adjoined on either end. If the
external diameter of the cylinder be 1.4 m and its length be 8 m, find the cost of painting it
on the outside at the rate of Rs. 10 per `m^2`.

Answer 1

Diameter of cylinder = 1.4m 

∴ Radius of cylinder = `(1.4)/2` = 0.7m

Height of cylinder= 8 m.

∴ S.A of tank = 2πrh + `2πr^2` 

= `2×22/7×0.7×8+2×22/7×(0.7)^2`

=`176/5+77/25`

=`957/25=38.28cm^2`

Now, cost of 1`m^2`= Rs.10.

∴ Cost of `38.28m^2 = Rs.[10× 38.28]` 

=Rs .382.80