Question 998710
L, Leslie
A, Anthony
N, Nancy
-
{{{system(L=2A+10,N=3L-40,A=A)}}}


Average Age:
{{{(L+N+A)/3}}}

{{{((2A+10)+N+A)/3}}}

{{{(2A+10+(3L-40)+A)/3}}}

{{{(2A+10+(3(2A+10)-40)+A)/3}}}

{{{(2A+10+6A+30-40+A)/3}}}

{{{(9A+10+30-40)/3}}}

{{{9A/3}}}


Average Age is  {{{9A/3=highlight(highlight(3A))}}}.
That is all you can do.  You have three unknown variables but just two linear equations.