The task is to generate the correct answer for a given math problem.
--------
Question: Problem: how many diagonals does a polygon with 13 sides have , if one of its vertices does not connect to any diagonal ?

Answer: 54

Question: Problem: a theater box office sold an average ( arithmetic mean ) of 65 tickets per staff member to a particular movie . among the daytime staff , the average number sold per member was 75 , and among the evening staff , the average number sold was 60 . if there are no other employees , what was the ratio of the number of daytime staff members to the number of evening staff members ?

Answer: 1 : 2

Question: Problem: a man sitting in a train which is travelling at 80 kmph observes that a goods train , travelling in opposite direction , takes 9 seconds to pass him . if the goods train is 280 m long , find its speed ?

Answer:
32 kmph