Question 1170627

let John's age be {{{x}}} and Nick's age {{{y}}}

if John is five times as old as Nick, we have

{{{x=5y}}}.......eq.1

if in {{{15}}} years time, John will be three times as old as Nick, we have

{{{x+15=3(y+15)}}}.......eq.2...substitute {{{x}}} from eq.1

{{{5y+15=3(y+15)}}}....solve for {{{y}}}

{{{5y+15=3y+45}}}

{{{5y-3y=45-15}}}

{{{2y=30}}}

{{{y=15}}}

 John is {{{15}}} years old