SOLUTION: In a rate of work problem, how do you set it up if it is phrased differently, as in "Joe can do a job in 3 hours, and working together with Charlie they completed the job in 2 hour

Algebra ->  Rate-of-work-word-problems -> SOLUTION: In a rate of work problem, how do you set it up if it is phrased differently, as in "Joe can do a job in 3 hours, and working together with Charlie they completed the job in 2 hour      Log On


   



Question 971758: In a rate of work problem, how do you set it up if it is phrased differently, as in "Joe can do a job in 3 hours, and working together with Charlie they completed the job in 2 hours, how long would Charlie take to do the job working alone?" I'm used to the more typical format where you are given each of their rates and then have to find each person's individual rate.
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
Joe (1/3) of job in an hour + Charlie (1/x) in an hour = 1/2 (of job in an hour)
Multiply by 6x common denominator.
2x + 6= 3x
x=6
Charlier does (1/6) of job per hour working alone. It takes him 6 hours to do it.