Question 772699
Let {{{ s }}} = the speed of the boat 
in still water ( no current )
{{{ s + 2 }}} = speed of boat going downstream
{{{ s - 2 }}} = speed of boat going upstream
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given:
{{{ s + 2 = 2*( s - 2 ) }}}
{{{ s + 2 = 2s - 4 }}}
{{{ s = 6 }}}
6 m/s is the speed of the boat without current