Q: The task is to generate the correct answer for a given math problem.
Problem: john can complete a given task in 10 days . jane will take only 20 days to complete the same task . john and jane set out to complete the task by beginning to work together . however , jane was indisposed 4 days before the work got over . in how many days did the work get over from the time john and jane started to work on it together ?
A:
8.5