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 1116 milliliters of the drug, how many milliliters of compound A are needed?

First step:

7 ml + 5 ml = 12 ml

Second step:

% of A = 7/12 x 100 = 58.33%

% of B = 5/12 x 100 = 41.67%

Third step:

In 1116 ml

compound A = 1116 x (58.33/100) = 651 ml

compound B = 1116 x (41.67/100) = 465 ml

Explanation:

In the 1st step: with what is given, the total volume is 12 ml

In the 2nd step: Find the percentage of each compound in the drug according to what is given.

In the 3rd step: calculate the volume of each compound separately in the new total volume of 1116 ml using the percentage composition.

volume of compound A will therefore be 651 milliliters