Question

A hemispherical tank, of diameter 3m, is full of water. It is being emptied by a pipe at the rate of $3\frac{4}{7}$ litre per second. How much time will it take to make the tank half empty?

Answer 1

Diameter of tank = 3m
$\therefore Radius=r=\frac{3}{2}m$
Volume of tank = $\frac{2\times \pi \times r^3}{3}=\frac{2\times 22\times 27}{3\times 7\times 8}=\frac{99}{14}Volumereleasedpersecond=3\frac{4}{7}litre=\frac{25}{7}Volumethatneedstoberemovedin{m}^3=\frac{1}{2}Volumeofthehemisphere=\frac{99}{2\times 14}1m^3=1000LVolumethatneedstoberemovedinL=\frac{99\times 1000}{28}Timetakentoremovethesaidvolume=\frac{99\times 1000}{28}\times \frac{7}{25}s=990s$