Question

This Christmas, your brother Jack will be 2 years from being twice as old as your sister Jen. The sum of Jacks age and three times Jen's age is 66. How old is Jen?

Answer 1

Age of Jen is 13.6 years old

Solution:

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

$x + 2 = 2y\\\\x = 2y - 2---- eqn 1$

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

y = 13.6

Thus age of Jen is 13.6 years old