Posted by sunil on Saturday, January 5, 2013 at 2:40pm.
find the number of seat in a theater
containing 30 rows if the first row has 14 seats and each row after that has 2 more seats than the previous row

math  drwls, Saturday, January 5, 2013 at 3:07pm
14 + 16 + ... 70 + 72
Avg. number per row = (14+72)/2 = 43
Totsl = 43*30 = 1290.