Question 1129747
Let {{{ t }}} = time in hrs required by Chris
to clean the Moose club
Add their rates of cleaning to get rate 
working together
{{{ 1/((5/4)*t) + 1/t = 1/4 }}}
{{{ 4/(5t) + 1/t = 1/4 }}}
Multiply both sides by {{{ 5*4t }}}
{{{ 16 + 20 = 5t }}}
{{{ 5t = 36 }}}
{{{ t = 7.2 }}} hrs
and
{{{ (5/4)*7.2 = 9 }}} hrs
Chris takes 7 hrs 12 min
John takes 9 hrs
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check:
{{{ 1/9 + 1/7.2 = .25 }}}
{{{ .11111 + .13888 = .25 }}}
{{{ .25 = .25 }}} 
OK