Question 969896
speed of the river,  r
speed of boat by itself, b


downstream  {{{72/3=24}}}

upstream  {{{60/6=10}}}


{{{system(b-r=10,b+r=24)}}}


If add the equations then
{{{2b=34}}}
{{{b=17}}}------boat speed without current


{{{r=-b+24}}}
{{{r=24-17}}}
{{{r=7}}}----------river current speed