<PRE><B>Question 292118</B>
One pump can fill a gasoline tank in 9 hours.
 With a second pump working simutaneously the tank can be filled in 5 hours.
 How long would it take the second pump to fill the tank operating alone?
:
Let x = 2nd pump time working alone
:
Let the completed job (full tank) = 1
:
A typical shared work equation
{{{5/9}}} + {{{5/x}}} = 1
multiply equation by 9x, results
5x + 9(5) = 9x
:
5x + 45 = 9x
:
45 = 9x - 5x
:
45 = 4x
x = {{{45/4}}}
x = 11.25 hrs, 2nd pump by itself
:
:
Check solution
{{{5/9}}} + {{{5/11.25}}} =
.56 + .44 = 1 

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