Area of Triangle with Given Sides

In triangle ABC, the lengths of sides AB, BC, and AC are represented by the variables $a$, $b$, and $c$ respectively. The angle $C$ measures $60^ ext{o}$, and the area of the triangle can be calculated using the formula:

$$ ext{Area} = rac{1}{2}ab imes ext{sin}(C)$$

Given that the area of triangle ABC is 30 square units, what is the value of $a + b$, if $a = 2b$?