Question 779625
L = Land
W = Water

{{{L+W=1}}};
{{{L=(3/5)W}}}.


The second equation rearranges to... not needed yet.
Substitute the second equation into the first equation and solve for W.

{{{(3/5)W+W=1}}}
{{{W(3/5+1)=1}}}
{{{W(8/5)=1}}}
{{{highlight(W=5/8)}}}, requiring that {{{highlight(L=3/8)}}}