SOLUTION: Tracey and Alan publish a 10-page independent newspaper once a month. At production, Alan usually spends 6 hours on the layout of the paper. When Tracey helps, layout takes 3 hours

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Tracey and Alan publish a 10-page independent newspaper once a month. At production, Alan usually spends 6 hours on the layout of the paper. When Tracey helps, layout takes 3 hours      Log On


   

Question 598688: Tracey and Alan publish a 10-page independent newspaper once a month. At production, Alan usually spends 6 hours on the layout of the paper. When Tracey helps, layout takes 3 hours and 20 minutes. How long it would take Tracey to do the job alone?
Answer by w_parminder(53) About Me  (Show Source):
You can put this solution on YOUR website!
Let time taken by Alan alone = A hrs (= 6 hrs)
time taken by Tracey alone = B hrs ( unknown )
and time taken when they work together = C hrs (= 3hrs 20min OR 10/3 hrs)
According to the formula
1%2FA%2B1%2FB=1%2FC
we get
1%2F6%2B1%2FB=3%2F10
1%2FB=3%2F10-1%2F6
1%2FB=4%2F30=2%2F15
therefore B =15/2
So Tracey alone would take 7 hours 30 minutes to complete the job