Working 5 hours a day, A can complete a work in 8 days and working 6 hours a day, B can complete the same work in 10 days. Working 8 hours a day, they can jointly complete the work in -

Question: Working 5 hours a day, A can complete a work in 8 days and working 6 hours a day, B can complete the same work in 10 days. Working 8 hours a day, they can jointly complete the work in -

Solution:
Working 5 hours a day, for 8 days, A can finish the work in = (5 × 8) = 40 hours
Working 6 hours a day, for 10 days, B can finish the work in = (6 × 10) = 60 hours

both together can do in one hour = 1/40 + 1/60
= (3 + 2)/120
= 5/120
= 1/24

so, it will take them 24 hours to do the work.

hence, working 8 hours a day, they need = 24/8 = 3 days