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

Input: Consider Input: Problem: the average of 6 no . ' s is 3.95 . the average of 2 of them is 3.8 , while the average of theother 2 is 3.85 . what is the average of the remaining 2 no ' s ?

Output: 4.2


Input: Consider Input: Problem: how many prime numbers are between 51 / 13 and 89 / 9 ?

Output: 2


Input: Consider Input: Problem: a boat running upstream takes 8 hours 48 minutes to cover a certain distance , while it take 4 hours to cover the same distance running downstream . what is the ratio between the speed of the boat and speed of the water current respectively ?


Output: 8 : 3