The last row in an audition contains 9 seats. Every other row in the auditorium contains 18 seats. There are 387 seats in the auditorium. How many rows are there in the auditorium?

22 rows

Step-by-step explanation:

Given there are 387 seats in the auditorium - each row contains 18 seats except the last row which contains 9 seats

Therefore

Number of rows in the auditorium = total number of seats divided by number of seats in each row

That's

387/18 = 21 remainder 9

The remaining 9 seats goes into the last row which contains only nine seats making 22 rows

So, there are 22 rows in the auditorium