SOLUTION: Carlo can type a manuscript for 10 hours. he started working then bobby joined him 2 hours later. they worked together for 4 hrs until carlo decided to stop and then bobby had to f

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Carlo can type a manuscript for 10 hours. he started working then bobby joined him 2 hours later. they worked together for 4 hrs until carlo decided to stop and then bobby had to f      Log On


   

Question 1181303: Carlo can type a manuscript for 10 hours. he started working then bobby joined him 2 hours later. they worked together for 4 hrs until carlo decided to stop and then bobby had to finish the manuscript alone. if bobby finished the remaining portion in 6 more hours, how long can he type the whole manuscript working alone?
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
Consider typing a manuscript is 1 job
Carlo takes 10 hours to do the job alone
So he does 1/10 of the job in 1 hour
in the first two hours he does 2/10 of the job ------------A
let bobby take x hours to do the job alpne
so he does 1/x of the job in 1 hour
together they do (1/10 +1/x ) of the job in 1 hour
they work together for4 hours.
so they do 4 (1/10 + 1/x ) job = 4(10+x)/10x = 2(10+x)/5x of the job-----B
Booby works for 6 hours
so he does 6/x of the job -------------C
A+B+c = 1 job
2/10 + 2(10+x)/5x + 6/x =1
Solve for x