The task is to generate the correct answer for a given math problem.
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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: find compound interest on $ 10000 at 15 % per annum for 2 years 4 months , compounded annually .

Answer: 3886.25


Question: Problem: two trains are running in opposite directions in the same speed . the length of each train is 120 meter . if they cross each other in 24 seconds , the speed of each train ( in km / hr ) is

Answer:
18