Answer
$7.5$ cups flour
Work Step by Step
To find how much flour is needed, first divide $5$ $\div$ $2$. This is so we see how many "sets" of pie crusts we are making. Because the recipe makes the crusts 2 crusts at a time, one "set" of crusts has 2 crusts.
So $5$ $\div$ $2$ is $2.5$. So we are making $2.5$ "sets" of crusts.
Each set of crusts takes $3$ cups of flour. So do $2.5$ (the number of sets we are making) times $3$ (the cups of flour needed to make one set of crusts)
So, $2.5$ $\times$ $3$ $=$ $7.5$
$7.5$ cups of flour are needed to make $5$ pie crusts.
