Question 1197145
An auditorium has 20 seats in the first row, 24 seats in the second row, 28 seats in the third row, and so on, and 30 rows of seats. How many seats are in the theatre?
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20 in the 1st row.
20 + 4*29 = 136 in the 30th row
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Avg = (20+136)/2 = 78
30*78 = 2340 seats total