Question

1: There are 11 rows of seats in a concert hall: 15 seats are in the 1st row, 18 seats in the 2nd row, 21 seats in the 3rd row, and so on. What's the explicit equation and the recursive equation?

2: If the price per ticket is 27$, how much will be the total sales for a one-night concert if all the seats are taken?

Answer 1

Explanation:

c.d.=21-18=18-15=3

y=15+3(x-1),x∈N,x≤18

recursive equation

a_{n}=a_{n-1}+3

2.

S_{18}=18/2{2×15+(18-1)×3}=9(30+51)=9×81=729

Total sales=729×27=19,683 $