Recipe Calculation?

Question

A recipe uses 3 cups of flour to 1 1/6 cups of milk. If you only have 2 cups of flour how much milk should I use?

Answer 1

3/(1 1/6)=2/m where m=amount of milk

3/(7/6)=2/m

cross multiply

3m=2(7/6)

3m=14/6

3m=7/3

multiply both sides by 1/3

m=(1/3)(7/3)

m=7/9 cups of milk

or,...

you only have 2/3 the amount of flour so you need 2/3 the amount of milk

(2/3)*(1 1/6)

(2/3)*(7/6)

14/18=7/9 cups of milk