Question 440460
Bill can do it in x hours alone
Joe can do it in x+2 hours
Bill does 1/x of the job every hour and 10/x in 10 hrs
Joe does 1/(x+2) of the job in one hour and 10/(x+2) in 10 hrs.
together they do one job in 10 hrs.
This tells that each of them takes more than 10 hrs alone.

10/x+10/(x+2)=1
about 19 hrs for Bill and about 21 hrs for Joe.
10/19 +10/21=1