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

[EX Q]: Problem: a can do a work in 15 days and b in 20 days . if they work on it together for 7 days , then the fraction of the work that is left is
[EX A]: 11 / 6

[EX Q]: Problem: a train 200 m long can cross an electric pole in 5 sec and then find the speed of the train ?
[EX A]: 144

[EX Q]: Problem: stacy has a 12 page history paper due in 12 days . how many pages per day would she have to write to finish on time ?
[EX A]:
1