Question

An oil tank has to be drained for maintenance. The tank is shaped like a cylinder that is 4 ft long with a diameter of 2.2 ft. Suppose oil is drained at a rate of 2.3 ft³ per minute. If the tank starts completely full, how many minutes will it take to empty the tank? Use the value 3.14 for 1, and round your answer to the nearest minute. Do not round any intermediate computations.

Answer 1

First we calculate the volume of cylinder by the formula

$V=\pi\times r^2\times h$

where r is radius(half diameter) and h the height

replacing

$\begin{gathered} V=3.14\times(1.1)^2\times4 \\ V=3.14\times1.21\times4 \\ V=15.7976 \end{gathered}$

Volume of the thank is 15.7976 cubic ft

to calculate the number of minutes we divide the volumen between the rate

$\frac{15.7976}{2.3}=6.8685$

then, it take 7 minutes to drained