2005 CEMC Gauss (Grade 7) Problems/Problem 9
A movie theatre has eleven rows of seats. The rows are numbered from to . Odd-numbered rows have seats and even-numbered rows have seats. How many seats are there in the theatre?
There are six odd-numbered rows (rows ). These rows have seats in total. There are five even-numbered rows (rows ). These rows have seats in total. Therefore, there are seats in total in the theatre. The answer is .