SOLUTION: John can finish a job two hours longer than Cris. after working for one hour,Cris joins him and complete the job in 3 more hours. how long would it take john to finish the job if h

Algebra ->  Rate-of-work-word-problems -> SOLUTION: John can finish a job two hours longer than Cris. after working for one hour,Cris joins him and complete the job in 3 more hours. how long would it take john to finish the job if h      Log On


   

Question 896951: John can finish a job two hours longer than Cris. after working for one hour,Cris joins him and complete the job in 3 more hours. how long would it take john to finish the job if he worked alone?
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Let x = time for Chris to do the job himself alone.

Rates of Work For Each Worker:
John, 1%2F%28x%2B2%29
Chris, 1%2Fx

RT=J for Rate, Time, Job.

Account for the 1 job which John and Chris do.
highlight_green%28%281%2F%28x%2B2%29%29%2A1%2B%281%2F%28x%2B2%29%2B1%2Fx%29%2A3=1%29.
This is amount of job John does in 1 hour plus amount of job both John and Crhis do together for 3 hours.
Solve for x and then evaluate x+2.

Begin recognizing the lowest common denominator is x(x+2); and multiply the members by this, and simplify.
Solve ...