Suppose that production for good X is characterized by the following production function, Q = K0.5, where K is the fixed input in the short run.

Suppose that production for good X is characterized by the following production function, Q = K0.5L0.5, where K is the fixed input in the short run. If the per-unit rental rate of capital, r, is $25 and the per-unit wage, w, is $15, then the fixed cost of using 81 units of capital and 9 units of labor is