SOLUTION: if 'a' can do a job in 4hrs and 'b' can do it in 6hrs, how long will it take if both do it together. and the eqaution to figure it out. ty

Question 319389: if 'a' can do a job in 4hrs and 'b' can do it in 6hrs, how long will it take if both do it together. and the eqaution to figure it out. ty
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Add their rates working separately to get
theirs rates working together
In words:
(1 job/a's time) + (1 job/b's time) = 1 job/working together

multiply both sides by

Working together, they can do the job in 2.4 hrs