Mathematics

Problem

A cylindrical water tank has an inner radius of

1\,\text{m}

and a height of

2\,\text{m}

. It is being filled by a pump that delivers water at

20\,\text{L s}^{-1}

while the tank leaks at

300\,\text{mL s}^{-1}

. How long, in minutes, will it take to fill the tank to

90\%

of its capacity? a) About

5.5\text{ min}

b) About

6.5\text{ min}

c) About

4.8\text{ min}

d) About

3.0\text{ min}