Wendy can build a doghouse in 15 hours, and Miguel can build an identical doghouse in 10 hours. How many hours will it take Wendy and Miguel, working together at their respective constant rates, to build a doghouse?

William and Stephanie are painting the bedrooms in their house. If he had to paint the bedrooms himself, it would take William 4 hours to complete the job. If Stephanie alone were to paint the bedrooms, it would take her 6 hours.Working together, how long will it take William and Stephanie to paint the bedrooms?

If Jim and Jerry work together they can finish a job in 4 hours. If working alone takes Jim 10 hours to finish the job, how many hours would it take Jerry to do the job alone?

Eight engineers with 2 technicians can design a house in 7 hours, which 25 engineers with 13 technicians can do in 2 hours. What fraction of the whole work, can be done in 1 hour by 11 engineers with 20 technicians?

Tom and Jerry working separately can finish a work in 60 and 45 days respectively. They begin the work together and after 15 days, Jerry goes away. In how many days will the work be completed by Tom alone?

If X can complete a job in 12 hours and Y can complete the same job in 8 hours, how long will it take them to complete the job working together? A)  3 hours B) 4 hours C) 6 hours D) 7.5 hours