Work problems are solved by first figuring out how much of the job they can do in each hour. Shawn can do 1/4 of the job in an hour and Ellie can do 1/6 of the job in an hour. 1/6+1/4=2/12+3/12=5/12. This means that they can do 5/12 of the job an hour. This means that together they can do the job in 2 2/5 hours. The foreman is obviously wrong because first of all Shawn can do it alone in 4 hours, so with Ellie he will do it faster, and second of all 2 2/5<5. Hope this helped!
