The 7-line t-shirt company manufactors t-shirts and sells them online. The company has a model where the cost C, in dollars, to make x t-shirts is given by the equation C = 40 3 x + 20 C = 40 3 ⁢ x + 20 and the revenue R, in dollars, made by selling x t-shirts is given by R = 15 x R = 15 ⁢ x . The break even point is where the cost and revenue equations intersect. How many t-shirts must the company sell to break even?