Answer:
32 polio vaccinations and 28 measles vaccinations.
Explanation:
Let p represent the number of polio vaccines and let m represent the amount of measles vaccines.
We know that each polio vaccine consists of 4 doses, and each measles vaccine consists of 2 doses.
Dr. Potter gave a total of 60 vaccinations last year. Therefore, the sum of the number of polio vaccines and measles vaccines must total 60. Therefore:

Together, they consisted of 184 doses.
Since each polio vaccine has 4 doses, the amount of doses for p polio vaccines is 4p.
And since each measles vaccine has 2 doses, the amount of doses for m measles vaccines is 2m.
So:

We now have a system of equations:

We can solve using elimination. Let’s multiply the first equation by -2. So:

Now, we can add this to the second equation. Hence:

Simplify:

Divide both sides by 2:

Therefore, Dr. Potter gave out 32 polio vaccinations.
By the first equation:

Substitute 32 for p to get:

So, 28 measles vaccinations were given out.