Age of Jen is 13.6 years old
<em><u>Solution:</u></em>
Let "x" be the age of Jack and "y" be the age of Jen
Given that This Christmas, your brother Jack will be 2 years from being twice as old as your sister Jen
The above sentence can be written mathematically as:
Jack age + 2 = twice of age of Jen
The sum of Jacks age and three times Jen's age is 66
Jack age + three times Jen age = 66
x + 3y = 66 ---- eqn 2
Substitute eqn 1 in eqn 2
2y - 2 + 3y = 66
5y - 2 = 66
5y = 68
<h3>y = 13.6</h3>Thus age of Jen is 13.6 years old