Jeff is designing the seating arrangement for a concert in his high school theater.

Question

Jeff is designing the seating arrangement for a concert in his high school theater. To give everyone a good view, each row must have 5 more seats than the row before it, and the 1st row can only have 12 seats. Help Jeff plan the rest of the seating by solving for how many seats are in row 25. Then explain to Jeff how to create an equation to predict the number of seats in any row. Show your work, and use complete sentences. (10 points)

Answer 1

To set up the table like below:

 

Row    Seats

(n)      (N)

1        12

2        12 + 5

3        12 + 2 X 5

4        12 + 3 X 5

5        12 + 4 X 5

6        12 + 5 X 5

.         ... ...

.         ... ...

.         ... ...

25      12 + 5 X 24 = 12 + 120 = 132

.         ... ...

.         ... ...

.         ... ...

n        12 + 5 x (n-1)

 

 

Suppose the number of row is n, the number of seats N in any row,

the equation would be:

N = 12 + 5 X (n -1)

 

The number of seats N is equal to 12 more than 5 times of the number of the previous row.

Answer 2

Hi Tiffany,

 

First row has 12 seats. Second row will have 12+5 = 17 seats, third row will have 17+5 = 22 seats and so on...

Let the number of seats in a given row r be y. Then, we can write

y = 5(r - 1) + 12

Then, row 25 will have

5(25 - 1) + 12 = 132 seats