A solid is composed of a cylinder with hemispherical ends.

Solution:

Height of the cylinder

$=108-36$

 

$=72 \mathrm{~cm}$

$r=18 \mathrm{~cm}$

C.S.A. of cylinder

$=2 \pi r h$

$=2 \pi \times 18 \times 72$

$=2 \times 3.14 \times 18 \times 72$

 

$=8138.88 \mathrm{~cm}^{2}$

C.S.A. of 2 hemisphere = surface of a sphere

$=4 \pi r^{2}$

Total surface

$=2 \pi r h+4 \pi r^{2}$

$=2 \pi r(h+2 r)$

$=2 \times 3.14 \times 18(72+2 \times 18)$

 

$=12214.54 \mathrm{~cm}^{2}$

Total cost

$=7 \times 12214.54$

$=85502$ Paise

 

$=855.02$ Rs.