Question:

The ratio of the total surface area to the lateral surface area of a cylinder whose radius is 20 cm and height 60 cm, is

(a) 2 : 1

(b) 3 : 2

(c) 4 : 3

(d) 5 : 3

Solution:

(c) 4 : 3

Here,

$\frac{\text { Total surface area }}{\text { Lateral surface area }}=\frac{2 \pi r(h+r)}{2 \pi r h}$

$=\frac{h+r}{h}$

$=\frac{20+60}{60}$

$=\frac{4}{3}$

$=4: 3$