Question

The radii of the bases of two cylinders are in the ratio $3:5$ and their heights are in the ratio $2:3$. The ratio of their curved surface will be:

• A. $2:5$
• B. $2:3$
• C. $3:5$
• D. $5:3$

Answer 1

Answer: (A)

$2:5$

Ratio of curved surfaces $=\frac{2\pi r_1{h}_1}{2\pi r_2{h}_2}=\left(\frac{r_1}{r_2}\right)\times \left(\frac{h_1}{h_2}\right)$
$=\frac{3}{5}\times \frac{2}{3}=\frac{2}{5}=2:5$