SOLUTION: It takes Leag 7 more hours to paint the kitchen than it thesez Henry to complete the same job. Together, they can completely pain the kitchen in 12 hours. How long does it take Hen

Algebra ->  Rate-of-work-word-problems -> SOLUTION: It takes Leag 7 more hours to paint the kitchen than it thesez Henry to complete the same job. Together, they can completely pain the kitchen in 12 hours. How long does it take Hen      Log On


   



Question 921199: It takes Leag 7 more hours to paint the kitchen than it thesez Henry to complete the same job. Together, they can completely pain the kitchen in 12 hours. How long does it take Henry to paint the kitchen if he works alone?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
t Henry's time
1%2F%28t%2B7%29+%2B+1%2Ft+=+1%2F12 |Multiplying thru by 12t(t+7) so as all denominators = 1
12t + 12(t+7) = t(t+7)
t^2 -17t -84 = 0 (tossing out negative solution for unit measure)
(t +4)(t-21) = 0
t = 21hr, Henry's time
And..checking
1/28 + 1/21 = 1/12
49/(28•21) = 1/12