Determine the seating capacity of an auditorium with 25 rows of seats if there are 20 seats in the first row, 24 in the second row, 28 in the third row, and so on.

The seats are increasing at a rate of four per row. If you were to write this in an equation, it would be y=4X+20, with 4 as the rate of change, 20 as the original amount of seats, and Y as the total number of seats for X rows. Plug in 25 for X and you'll get an answer of 120 seats.