SOLUTION: Ghanima can correct a stack of papers in 5 hours, and Thufir can correct them in 4 hours. How long does it take them to correct the papres together?

Question 937792: Ghanima can correct a stack of papers in 5 hours, and Thufir can correct them in 4 hours. How long does it take them to correct the papres together?

Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
Ghanima can correct a stack of papers in 5 hours, and Thufir can correct them in 4 hours.
How long does it take them to correct the papres together?
:
Let t = time required when working together
let the completed job = 1 (the stack of papers)
:
Each will do a fraction of the job, the two fractions add up to 1
+ = 1
multiply by 20,
20* + 20* = 20
cancel out the denominators and you have
4t + 5t = 20
9t = 20
t = 20/9
t = 2.22 hrs, which is 2 + .22(60) = about 2 hrs 13 min

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