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

Ex Input:
Problem: two trains running in opposite directions cross a man standing on the platform in 37 seconds and 27 seconds respectively and they cross each other in 29 seconds . the ratio of their speeds is :

Ex Output:
1 :

Ex Input:
Problem: a group of students decided to collect as many paise from each member of group as is the number of members . if the total collection amounts to rs . 46.24 , the number of the member is the group is :

Ex Output:
68

Ex Input:
Problem: the probability of two events a and b are 0.25 and 0.40 respectively . the probability that both a and b occur is 0.15 . the probability that neither a nor b occur is _________

Ex Output:
0.5