# The sum of the ages of two sisters is 12 years, and the difference in their ages is 6 years. What are their ages?

Jan 10, 2017

They are 9 and 3.

#### Explanation:

Let one of them be $a$ years and the other be $b$ years
So $a + b = 12$ equation 1
And $a - b = 6$ equation 2

Add equation 1 and equation 2
$2 a = 18$
$a = 9$

$a + b = 12$
So $b = 3$