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 b

Question

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

Answer 1

You don't say how many seats are in the first row, so let's call that s.

 

Row 2would have s + 5 seats.

 

Row 3 would have (s + 5) + 5 = s + 10.

 

Etc.

 

What you have is an arithmetic sequence, where the first number is s, and the increment between numbers in the sequence is 5.  So the n^th row would have s + 5(n-1) seats.  The 25^th row would have s + 5(25 - 1) = s + 5*24 = s + 120 seats.

 

If you know how many seats are in the first row, you can substitute that for s to get the exact numbers.