Question

A cylindrical water flask has a hemispherical cap which exactly fits on the flask. The height and radius of the flask are 20 cm and 3 cm respectively. If the cap is used as the cup to drink water, how many cups of water can be served.

___

Answer 1

No. of cups that can be served = $\frac{Volumeoftheflask}{Volumeofthecup}$

= $\frac{\pi r^{2}h}{\frac{2}{3}\pi r^3}$

= $\frac{\pi \times 3^2\times 20}{\frac{2}{3}\pi \times 3^3}$

= 10 cups