Question

A storage tank consist of a circular cylinder with a hemisphere stuck on either end. If the external diameter of the cylinder be 1.4m.and its length be 8m. find the cost of painting it on the outside at rate of rupees 20perm

Answer 1

r of hemisphere = r of cylinder = 1.4/2=0.7m=70cm

= h of hemisphere

h of cylinder =800-70-70 = 800 -140 = 660 cm

So Area to be painted

= 2×22/7× 70×660 + 2 ×22/7×70×70

=290400 + 30800

=32.12 m²

So Cost =Area × rate =32.12 × 20 = 642.40

= Approx 642 Rs