A toy is in the form of a cylinder with hemispherical ends.

Solution:

We have,

the total height of the toy $=90 \mathrm{~cm}$ and

the radius of the toy, $r=\frac{42}{2}=21 \mathrm{~cm}$

Also, the height of the cylinder, $h=90-42=48 \mathrm{~cm}$

Now, the total surface area of the toy $=$ CSA of cylinder $+2 \times$ CSA of a hemisphere

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

$=2 \pi r(\mathrm{~h}+2 r)$

$=2 \times \frac{22}{7} \times 21 \times(48+2 \times 21)$

$=44 \times 3 \times(48+42)$

$=44 \times 3 \times 90$

$=11880 \mathrm{~cm}^{2}$

So, the cost of painting the toy $=\frac{11880 \times 70}{100}=$ Rs 83,16