SOLUTION: Suppose I paint a wall in 10 hours, and you and I together paint a wall in 2 hours. How much faster do you paint a wall than I?

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Question 696478: Suppose I paint a wall in 10 hours, and you and I together paint a wall in 2 hours. How much faster do you paint a wall than I?
Found 2 solutions by ankor@dixie-net.com, josmiceli:
Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website!
Suppose I paint a wall in 10 hours, and you and I together paint a wall in 2 hours.
How much faster do you paint a wall than I?
:
Let t = time for you to paint the wall
:
Let the completed job = 1 (A painted wall)
:
A shared work equation
+ = 1
Multiply by 10t, results
2t + 10(2) = 10t
20 = 10t - 2t
20 = 8t
t = 20/8
t = 2.5 hrs
:
10 - 2.5 = 7.5 hrs faster

Answer by josmiceli(19441) (Show Source):
You can put this solution on YOUR website!
My rate is ( 1 wall ) / ( 10 hrs )
Together our rate is ( 1 wall ) / ( 2 hrs )
---------
Let your rate = ( 1 wall ) / ( t hrs )
---------
Add our rates to get our rate working together

Multiply both sides by

and

You can paint the wall in 7.5 hrs less time
than I can