SOLUTION: Shawn and Ellie are construction workers. Shawn can complete a concrete job in 4 hours, while Ellie can complete it in 6 hours. The foreman says that it will take them 5 hours to c

Algebra ->  Equations -> SOLUTION: Shawn and Ellie are construction workers. Shawn can complete a concrete job in 4 hours, while Ellie can complete it in 6 hours. The foreman says that it will take them 5 hours to c      Log On


   

Question 828316: Shawn and Ellie are construction workers. Shawn can complete a concrete job in 4 hours, while Ellie can complete it in 6 hours. The foreman says that it will take them 5 hours to complete it if they work together. Explain each step in solving this equation and determine if the the Foreman is correct or not.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Shawn's rate is ( 1 job ) / ( 4 hrs )
Ellie's rate is ( 1 job ) / ( 6 hrs )
Let +t+ = time for them to do the job together
+1%2F4+%2B+1%2F6+=+1%2Ft+
Multiply both sides by +12t+
+3t+%2B+2t+=+12+
+5t+=+12+
+t+=+2.4+ hrs
The foreman is wrong