Question 176700
Let J = the age of your husband, John, in 2000 and let W = the age of your son, William in 2000.
From the problem description, you can write:
In 2000: 
{{{J = 11W}}} "...John was 11 times as old as...William."
12 years later in 2012, when both of them are 12 years older, you can say:
{{{J+12 = 3(W+12)}}} Simplifying this, we get:
{{{J+12 = 3W+36}}} Now we substitute, from above, {{{J = 11W}}}
{{{(11W)+12 = 3W+36}}} Subtract 3W form both sides of this equation.
{{{8W+12 = 36}}} Now subtract 12 from both sides.
{{{8W = 24}}} Finally, divide both sides by 8.
{{{W = 3}}}
Your son was 3 years old in 2000.