Question

A certain drug is made from only two ingredients: compound A and compound B. There are 5 milliliters of compound A used for every 3 milliliters of compound B. If a chemist wants to make 656 milliliters of the drug, how many milliliters of compound A are needed?

Answer 1

Answer:    410 mL

=====================================================

Explanation:

The ratio of A to B is 5:3

Multiply both parts by x to get 5x:3x

We need 5x parts of A and 3x parts of B

Adding those parts should get us 656 mL total

A+B = total

5x+3x = 656

8x = 656

x = 656/8

x = 82

Therefore, we need 5x = 5*82 = 410 mL of compound A

Also, we need 3x = 3*82 = 246 mL of compound B

In total, we have A+B = 410+246 = 656 mL which helps confirm the answer.

-----------

Side note: The ratio  410:246 reduces to 5:3 after dividing both parts by 82.