Question

a father and his son clean the house together in 2 hours. when the son works alone, it takes him an hour longer to clean than it takes his dad alone. find how long it takes the son to clean alone.

Answer 1

It takes the son one and half hours to clean the house. To find this you need the equations F+S=2 and F+1=S. (F=father and S=son) You take the F+1 and substitute it in for S in F+S to get F+(F+1)=2. Then you combined like factors, 2F+1=2, and simplify to get F=.5hr. After this you plug .5 in to F+1=S to get (.5)+1=S, meaning it takes the son 1.5 hour to clean the house.