Question

At a pharmacy, the ratio of containers of a brand-name

prescription medicine to the generic version of that
medicine is 7:2. If the pharmacy adds 6 more containers
of the generic version to its inventory, the ratio becomes
11:4. What was the original total number of containers of
the two medicines in stock?

Answer 1

• brand-name: 77
• generic: 22

Explanation:

We can answer this question by expressing both ratios so they have the same number for "brand-name medicine".

Before addition:

brand-name : generic = 7 : 2 = 77 : 22 . . . . . multiply by 11

After addition:

brand-name : generic = 11 : 4 = 77 : 28 . . . . . multiply by 7

We notice that the revised ratios have the "after" version of the "generic" as 28-22 = 6 more than the "before" version. This suggests that the revised ratios reflect actual inventory.

The original numbers of containers were ...

• brand-name: 77
• generic: 22