## Basic College Mathematics (9th Edition)

$\displaystyle \frac{203}{3}=67\frac{2}{3}$ quarts
We know that we need to use $7\frac{1}{4}$ quarts of additive for each tank of fuel. Therefore, if we have $9\frac{1}{3}$ tanks, the amount of additive must be the product of these two numbers. First, we estimate the result by rounding to the nearest whole number: $Additive\approx 7*9=63$ quarts Now, we get the precise answer: $Additive=\displaystyle 7\frac{1}{4}*9\frac{1}{3}=\frac{29}{4}*\frac{28}{3}=\frac{29*28}{3*4}=\frac{29*7}{3}=\frac{203}{3}=67\frac{2}{3}$ quarts