Science:Math Exam Resources/Courses/MATH104/December 2016/Question 13/Statement

A bucket is $60{\text{cm}}$ high, has a radius of $40{\text{cm}}$ at the top and $10{\text{cm}}$ at the bottom. Water is being dumped into the bucket at a rate of $1{\text{L}}/{\text{min}}$. How fast is the water level rising when the water is 30 cm deep? You may use the fact that the volume of a trunctated cone with height ${\textstyle h}$, radius at the bottom ${\textstyle r_{1}}$ and radius at the top ${\textstyle r_{2}}$, is given by ${\textstyle V={\frac {1}{3}}\pi h(r_{2}^{2}+r_{1}r_{2}+r_{1}^{2})}$.