Question 1137922
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The sum of the ages of Mike and Dan is 20 years. In four more  years Dan's age will be a 3/4 of mikes age.  How old is Mike now?
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{{{system(m+d=20,d+4=(3/4)(m+4))}}}


{{{system(d=20-m,4(d+4)=3(m+4))}}}


{{{4(20-m+4)=3m+12}}}

{{{80-4m+16=3m+12}}}

{{{80+16-12=3m+4m}}}

{{{84=7m}}}

{{{highlight(m=12)}}}