<PRE><B>Question 1090886</B>
Allison does a route in 60 minutes; with her assistant working with her, the route is done in 40 minutes.
 How long would it take the assistant to do the route by herself?
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let t = time required by the assistant working alone
let the completed job = 1
:
A typical shared work equation 
Each does a fraction of the job; the two fractions add up to 1
{{{40/60{}}} + {{{40/t}}} = 1
multiply equation by 60t, cancel the denominators
40t + 60(40) = 60t
40t + 2400 = 60t
2400 = 60t + 40t
2400 = 20t
t = 2400/20
t = 120 min, the assistant alone
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Just looking at it you can see Al did 2/3 and Assistant did 1/3</PRE>