In sacramento county, there are 80 teachers to every 4 teacher assistants. if there are 33,500 teachers, how many teacher assistants are there in the county?

For this case we can make the following rule of three:
 80 teachers -----------------> 4 teacher assistants
 33500 teachers ------------> x
 From here, we clear the value of x.
 We have then:
 
 Therefore we have 1675 teacher assistants in the county.
 
 There are 1675 teacher assistants in the county.