SOLUTION: The balcony of a theater has 12 rows of seats. The last row contains 8 seats, and each of the other rows contains one more seat than the rows behind it. How many seats are there in

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Question 1047550: The balcony of a theater has 12 rows of seats. The last row contains 8 seats, and each of the other rows contains one more seat than the rows behind it. How many seats are there in the balcony?
Found 2 solutions by jorel555, ikleyn:
Answer by jorel555(1290) About Me  (Show Source):
You can put this solution on YOUR website!
If the last row contains 8 seats, then the row directly in front has 9 seats; the next row has ten, and so on. So:
8+9+10+.....+19=162 seats in the balcony.

Answer by ikleyn(52781) About Me  (Show Source):
You can put this solution on YOUR website!
.
Arithmetic progression with the first term 8 and the common difference 1.

On arithmetic progressions, see the lessons
    - Arithmetic progressions
    - The proofs of the formulas for arithmetic progressions
    - Problems on arithmetic progressions
    - Word problems on arithmetic progressions
    - Chocolate bars and arithmetic progressions
    - Solved problems on arithmetic progressions

OVERVIEW of my lessons on arithmetic progressions with short annotations is in the lesson  OVERVIEW of lessons on arithmetic progressions.
in this site.