Question 975576

let Lisa's age be {{{x}}} and Maggie's age {{{y}}}

given:

Lisa is three times as old as Maggie. 

{{{x=3y}}}..........eq.1


The difference in their ages is {{{12}}} years.

{{{x-y=12}}}.........eq.2.....substitute {{{x}}} from eq.1

{{{3y-y=12}}} 

{{{2y=12}}}

{{{highlight(y=6)}}}

now, go to eq.1 and find {{{x}}}

{{{x=3y}}}..........eq.1

{{{x=3*6}}}

{{{highlight(x=18)}}}


so, Lisa is {{{18}}} years old and Maggie is {{{6}}} years old