Question 1099371
He ran the hot water for {{{ 3 }}} min
The tub was then {{{ 3/9 = 1/3 }}} filled
{{{ 2/3 }}} of the tube still empty
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He ran both hot and cold water for {{{ 1 }}} min
{{{ 1/9 + 1/6 = x/1 }}} where {{{ x }}} = 
The fraction of {{{ 2/3 }}} of the tub filled
in {{{ 1 }}} min
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Multiply both sides by {{{ 6*9 = 54 }}}
{{{ 6 + 9 = 54x }}}
{{{ x = 15/54 }}}
{{{ x = 5/18 }}}
and
{{{ ( 5/18 )*( 2/3 ) = 5/27 }}}
There is 
{{{ 9/27 + 5/27 = 14/27 }}} filles
There is {{{ 13/27 }}} left to be filled
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{{{ 1/9 + 1/6 - 1/4 = ( 13/27 )/t }}}
Multiply both sides by {{{ 108t }}}
{{{ 12t + 18t - 27t = 52 }}}
{{{ 3t = 52 }}}
{{{ t = 17.333 }}} min
{{{ .333*60 = 20 }}} sec
It takes 17 min and 20 sec to fill the tub
after the plug was pulled
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Definitely get a 2nd opinion on this.
I could easily make a mistake!