Question 934862
r and d, their ages now.
{{{system(r=7d,(r+5)=5*(d+5))}}};
If this makes sense, then you have some important understanding.  Solve the system for r and d.



{{{5d+25=r+5}}}
{{{5d+20=r}}}
-
{{{r=7d=5d+20}}}
{{{2d=20}}}
{{{highlight(d=10)}}}


{{{highlight(r=70)}}}