Question 1123140

{{{x}}}=age of Sara
{{{3x}}}=age of Ralph

after {{{6}}} years:

{{{x+6}}}=age of Sara
{{{3x+6}}}=age of Ralph, where he will be {{{twice}}} as old as Sara

so that:

{{{3x+6=2(x+6)}}}
{{{3x+6=2x+12}}}
{{{3x-2x=12-6}}}
{{{x=6}}}

Therefore:

{{{x=6}}} => age of Sara
{{{3x=3(6)=18}}} => age of Ralph