Question

Two cylinders have their radii in the ratio 4:5 and their heights in the ratio 5:6. Then, the ratio of their volumes is

• A. 15:11
• B. 8:15
• C. 5:9
• D. 8:21

Answer 1

The correct option is B 8:15

$r_1:r_2=4:5$
$h_1:h_2=5:6$
$\therefore V_1:V_2=\pi \times 4\times 5:\pi \times 5^2\times 6$ (V=$\pi r^{2}h$)
=$\pi \times 16\times 5\pi \times 25\times 6$
=$80\pi :150\pi$
$=8:15$