Question

the cost painting the total outside surface of a closed cylindrical oil tank at 75paise per sq dm is 288. the height of the tank is 5times the radius of the base of the tank find its volume

Answer 1

Since the cylinder is closed, the total surface area =(2×3.142r) + (curved surface area)

The radius=R, the height =5r

The S. A=(6. 284r)+(2×3.142r×5r)

(6.284r+31.42r^2) square dm

75×(6.284r+31.42r^2)=288

6.284r(1+5r)=3.84

0.6110=r(1+5r)
r+5r2-0.6110

Using the quadratic formulae we get
r =1.222dm

The h =5×1.222=6.11dm

The volume =3.142×6.11×1.222×1.222=28.57dm3