Question 966399
Add their rates of working:
Ryan's rate:
[ 1 hole dug ] / [ 5 hrs ]
Castle's rate:
[ 1 hole dug ] / [ 6 hrs ]
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Let {{{ t }}} = their time in hrs working together
{{{ 1/5 + 1/6 = 1/t }}}
Multiply both sides by {{{ 30t }}}
{{{ 6t + 5t = 30 }}}
{{{ 11t = 30 }}}
{{{ t = 2.727 }}}
{{{ .727*60 = 44 }}}
It will take them 2 hrs 44 min working together
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check:
{{{ 1/5 + 1/6 = 1/t }}}
{{{ 1/5 + 1/6 = 1/2.727 }}}
{{{ .2 + .1667 = .3667 }}}
{{{ .3667 = .3667 }}}
OK