The first row of a concert hall has 20 seats, and each row after the first has one more seat than the row before it. There are 30 seats.

Question

a)write a rule for the number of seats in the nth row
b) 40 students from a class want to sit n the same row.how close can they sit?

For (A) I got n+19 and for (B) I got 21

Answer 1

S(n) = 20 + (n-1) which is indeed n+19

n+19 = 40
so
n = 21