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 Question from Angela, a parent: a waste oil tank is 5 feet wide and 20 feet long, the empty tank on your truck holds 5000 gallons. If 7.48 gallons are in every cubic foot, what is the maximum depth the oil can be to completely fit into your truck?

Hi Angela,

There are 7.48 gallons per cubic foot and hence 5000 gallons is $\large \frac{5000}{7.48} \normalsize = 668.45 \mbox{ cubic feet.}$

Suppose the depth of oil in the tank is $d$ feet then the volume of oil in the tank is $5 \times 20 \times d \mbox{ cubic feet.}$ Thus

$5 \times 20 \times d = 668.45 \mbox{ cubic feet.}$

Solve for $d.$

Penny

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