Question 912742
Uniform Rates for Travel, <b>RT=D</b> rate time distance


Let r be the rate Gertrude would row if no river current
Let c be the rate of the river, the rate of flow of the river current


_________________rate________time__________distance
DOWNSTREAM_______r+c____________4_____________24
UPSTREAM_________2r-c___________4_____________24


Note very carefully, "the rate of the boat in still water was doubled".


Downstream Equation:  {{{(r+c)*4=24}}}
Simplify: {{{r+c=6}}}
Upstream Equation:  {{{(2r-c)*4=24}}}
Simplify:  {{{2r-c=6}}}


Solve this system for r and c:
{{{highlight(system(r+c=6,2r-c=6))}}}