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

[EX Q]: Problem: 1370 , x , 1070 , - 180 , - 6430
[EX A]: 1320

[EX Q]: Problem: a father said to his son , ` ` i was as old as you are at the present at the time of your birth ' ' . if the father ' s age is 52 years now , the son ' s age 5 years back was :
[EX A]: d ) 21

[EX Q]: Problem: a man performs 3 / 5 of the total journey by rail , 17 / 20 by bus and the remaining 6.5 km on foot . his total journey is :
[EX A]:
130 km