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

Example Input: Problem: 1370 , x , 1070 , - 180 , - 6430
Example Output: 1320

Example Input: Problem: set s contains exactly 10 numbers and has an average ( arithmetic mean ) of 6.2 . if one of the numbers in set s is increased by 7 , while all other numbers remain the same , what is the new average of set s ?
Example Output: 6.

Example Input: Problem: two goods trains each 500 m long are running in opposite directions on parallel tracks . their speeds are 50 km / hr and 30 km / hr respectively . find the time taken by the slower train to pass the driver of the faster one ?
Example Output:
45