The River Ridge High School auditorium has exactly 27 rows of seats. The rows are labeled, in order, from the front of the auditorium to the back from A through AA. There are 9 seats in the row A. Each row after the first row has three more seats than the previous row. How many seats are there in row AA?

Question

Mathematics

Nina Hogan

15 March, 20:00

The River Ridge High School auditorium has exactly 27 rows of seats. The rows are labeled, in order, from the front of the auditorium to the back from A through AA. There are 9 seats in the row A. Each row after the first row has three more seats than the previous row. How many seats are there in row AA?

+4

Answers (2)

Know the Answer?

Mathis · Answer 1

Answer: 95 seats

Step-by-step explanation:

I added 3 to each row starting with the 9 seats, up to 27 rows.

Ally Roberts · Answer 2

87

Step-by-step explanation:

The numbers of seats in each row form an arithmetic sequence. The general term (an) of such a sequence is given in terms of the initial value (a1) and the common difference (d) as ...

an = a1 + (n-1) ·d

The 27th term of the sequence with first value 9 and common difference 3 is ...

a27 = 9 + (27-1) ·3 = 9 + 78 = 87

There are 87 seats in row AA.