Question 1120649
a, Alvin
c, Chris

{{{system(a=(5/6)c,(a+10)+(c+10)=42)}}}

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{{{system(6a=5c,a+c=42-20)}}}


{{{system(a+c=22,6a=5c)}}}


{{{6a=5(22-a)}}}


{{{6a=110-5a}}}

{{{11a=110}}}



{{{system(NOW,a=10,c=12)}}}


Eleven years from now, ratio of their ages:
{{{(10+11)/(12+11)}}}, Alvin to Chris