Answer:
There were 32 polio vaccinations and 28 measles vaccination.
Step-by-step explanation:
Let number of polio vaccination be = x
Let number of measles vaccination be = y
Each polio vaccination consists of 4 doses, and each measles vaccination consists of 2 doses. Last year, Dr. Potter gave a total of 60 vaccinations that consisted of a total of 184 doses.
So, the two equations that form are:
or
.....(1)
And
.....(2)
Substituting value of x from (1) in (2)

=> 
=> 
=> 
=> 
Cancelling out negative sign

y = 28
And 
x = 32
Therefore, there were 32 polio vaccinations and 28 measles vaccination.