A man working 8 hours a day takes 5 days to complete a project. How many hours a day must he work to complete it in 4 days?
P can complete a work in 12 days working 8 hours a day. Q can complete the same work in 8 days working 10 hours a day. If both P and Q work together, working 8 hours a day, in how many days can they complete the work?
Ted can complete a work in 8 days working 12 hours a day. Sid can complete the same work in 16 days working 5 hours a day. If both Ted and Sid work together, working 6 hours a day, in how many days can they complete the work?