Help with ratios.

Question

A certain drug is made from only two ingredients: compound A and compound B. There are
7
milliliters of compound A used for every
5
milliliters of compound B. If a chemist wants to make
984
milliliters of the drug, how many milliliters of compound A are needed?

Answer 1

A is 7/12 of the drug

7/12 x 984 = 7(984)/12 = 7(82) = 574 ml of compound A

5/12 of 984 = 5(984)/12 =5(82) =410 ml of compound B