Question 1175129

let Blake ‘s age be {{{B}}} and Mackenzie's age {{{M}}}

if the sum of the ages of Blake and Mackenzie is {{{68}}} years, we have

{{{B+M=68}}}....solve for {{{B}}}

{{{B=68-M}}}....eq.1

 if  {{{8}}} years ago Blake's age was {{{3}}} times Mackenzie's age, we have

{{{B-8=3(M-8)}}}....eq.2......substitute {{{B}}}
{{{68-M-8=3M-24}}}
{{{68+24-8=3M+M}}}
{{{84=4M}}}
{{{84/4=M}}}
{{{M=21}}}

go to

{{{B=68-M}}}....eq.1....substitute {{{M}}}
{{{B=68-21}}}
{{{B=47}}}

answer: Blake  is {{{47}}} years old now