#### Answer

$\frac{7}{4}$ cups

#### Work Step by Step

One recipe calls for 3$\frac{1}{2}$ cups of milk, which equals $\frac{7}{2}$ cups of milk. Since she wants to make one-half of the recipe, she must use one-half of the milk needed for one recipe
We divide $\frac{7}{2}$ by 2
$\frac{7}{2}$ $\div$ 2 = $\frac{7}{2}$ $\times$ $\frac{1}{2}$
Multiply the numerators by each other, and multiply the denominators by each other:
$\frac{7}{2}$ $\times$ $\frac{1}{2}$ = $\frac{7}{4}$
She will use $\frac{7}{4}$ cups.