How many cups of water are needed for each cup of milk?

Question

A recipe requires 1/3 cup of milk for each 1/4 cup of water. How many cups of water are needed for each cup of milk?

A 1/12

B 3/4

C 11/12

D 1 1/3

Answer 1

Let's set up an algebraic equation to reflect the ratio of milk to water. We know that for every 1/3 cup of milk, we have 1/4 cup of water, so we can take:

1/3*m=1/4*w

How might we make that 1/3 cup into 1 cup of milk? We multiply by 3! What we do to one side we have to do to the other otherwise we change the equation (and break math), so we will multiply both sides by 3.

(1*3)/3*m=(1*3)/4*w

3/3*m=3/4*w

m=3/4w

Now think about how this new equation reflects the new ratio of milk to water...Which choice does that reflect?