Question 541991
Add their rate of filling
Joe's rate: ( 1 pool ) / ( 4 hrs )
Jim's rate: { 1 pool ) / ( 6 hrs )
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Let {{{t}}} = time in hours to fill pool with both filling
{{{ 1/4 + 1/6 = 1/t }}}
Multiply both sides by {{{ 12t }}}
{{{ 3t + 2t = 12 }}}
{{{ 5t = 12 }}}
{{{ t = 2.4 }}}
{{{ .4*60 = 24 }}}
Together they fill pool in 2 hrs and 24 min