Three painters, Beth, Bill, and Edie, working together, can paint the exterior of a home in 12 hours. Bill and Edie together have painted a similar house in 15 hours. One day, all three worked on this same kind of
house for 5 hours, after which Edie left. Beth and Bill required 10 more hours to finish. Assuming no gain or
loss in efficiency, how long should it take each person to complete such a job alone?