00:01
So in this problem, we're told that a corner section of a football stadium has 15 seats in the first row, and then there's a total of 40 rows.
00:08
And we're told that each successive row contains two additional seats.
00:12
You want to know how many seats are in the section in total? well, we can think of this like an arithmetic sequence.
00:18
Well, the first row has 15 seats.
00:20
And then they say each additional row has two more seats.
00:23
So the second row would have 17, the third would have 19, the fourth would have 21, and so forth.
00:30
But we know that there's 40 rows in total, meaning that there's 40 terms in the sequence, meaning that n would equal to 40.
00:37
Well, if we want to figure out how many seats are in this section, we're trying to figure out the sum.
00:42
So we can use our sum formula...