<PRE><B>Question 696478</B>
 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
{{{2/10}}} + {{{2/t}}} = 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
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