Arithmetic Series - Problem 10

You can use an arithmetic series formula to calculate the number of seats in a theater. Here, we do an example with multiple sections (which ends up being a couple of series added together,) but you can apply this strategy to any theater situation. You need to know how many seats are in the first row, which is your first term, how many are added in each successive row, which is d, and how many rows total there are, which represent your nth term. You might need to find these numbers for multiple sections. Plug those numbers from each section into the formula for an arithmetic series to find out how many seats total are in that section.