The task is to generate the correct answer for a given math problem.

Problem: two tains of equal lengths take 10 seconds and 15 seconds respectively to cross a telegraph post . if the length of each train be 120 metres , in what time ( in seconds ) will they cross each other travelling in opposite direction ?
12

Problem: mary can do a piece of work in 26 days . rosy is 30 % more efficient than mary . the number of days taken by rosy to do the same piece of work is ?
20

Problem: a fair coin is tossed 5 times . what is the probability that it lands heads up at least twice ?

13 / 16