Question

there were 170 people at the concert. If 85% of the seats were filled how many seats are in the auditorium

Answer 1

There are 200 seats in the auditorium. 170 / 0.85 = 200. 

Answer 2

In order to compute for the number of seats available in the auditorium, you just have to divide the number of people at the concert with the percentage of its utilized capacity.

Solution:

170 people / 85% = 200 seats available in the auditorium

To check the answer:

200 seats x 85% = 170 people are in the concert