One person can complete a piece of work in 8 days while other person can complete the same work in 4 days(if both works 10 hours per day). how many hours are required to complete the same work if both persons do it combined?
A = 1/8 job/day
B = 1/4 job/day
A + B = 3/8 job /day
which is 8/3 days per job
(8 days/3 jobs) 10 Hours/day
= 80/3 hours/job
= 26 2/3 hours