John uses 1 1/2 cups of milk and 3 cups of flour for his favorite cookie recipe. This makes 5 dozen cookies. Write and solve two proportions to see how much milk and flour he would need to make half as many cookies.

Fraction division is basically multiplication of a reciprocal.

For example (1/4)/(1/8) = (1/4)x(8/1)=2

Multiplication of the answer and the piece that divides (in this case 2 x 1/8), you should get the piece that is being divided (in this case 1/4). If that is correct, then your division is correct.