Question

An oil tank has to be drained for maintenance. the tank is shaped like a cylinder that is 4.5 ft long with a diameter of 2.2 ft . suppose oil is drained at a rate of 1.7 ft3 per minute. if the tank starts completely full, how many minutes will it take to empty the tank?

Answer 1

If the diameter of the cylinder is 2.2 ft, then the radius is 1.1 ft. What you want to find is the volume of the oil tank, which is the area of the base (pi*r^2 = 3.14*1.1*2) multiplied by the length (4.5 ft), which is 17 ft^3. Then, divide this volume by the rate at which it is being drained, getting (17ft^3/1.7ft^3)*minutes, and the units cancel out to make the answer:
10 minutes.