Question 1006736
Let {{{ d }}} = distance in mi that boat drifts downstream
{{{ d }}} is also the distance the boat goes back upstream
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The speed of the river is {{{ 5 }}} mi/hr
{{{d = r*t }}}
{{{ t = 12  }}} hrs
{{{ d = 5*12 }}}
{{{ d = 60 }}} mi
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Going back upstream, 
let {{{ s }}} = the speed of the boat in mi/hr in still water
{{{ s - 5 }}} = the speed of the boat going upstream
{{{ 60 = ( s - 5 )*22 }}}
{{{ 60 = 22s - 110 }}}
{{{ 22s = 170 }}}
{{{ s = 7.727 }}} 
The speed of the boat in still water is 7.727 mi/hr