Row 15 has 41 seats, and the entire section has 493 seats.
We can write the explicit formula for an arithmetic sequence to represent this, since we add 2 each time:
13+2(n-1)
Using 15 for n,
13+2(15-1) = 13+2(14) = 13+28 = 41
To find the total number of seats, we evaluate the sum
[tex]\Sigma_{n=1}^{17} 13+2(n-1)[/tex]
Using technology to evaluate this sum, it is 493.