2012 AMC 8 Problem 21

Marla has a large white cube that has an edge of 10 feet. She also has enough green paint to cover 300 square feet. Marla uses all the paint to create a white square centered on each face, surrounded by a green border. What is the area of one of the white squares, in square feet?

\textbf{(A)}\ 5\sqrt2\qquad\textbf{(B)}\ 10\qquad\textbf{(C)}\ 10\sqrt2\qquad\textbf{(D)}\ 50\qquad\textbf{(E)}\ 50\sqrt2

Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.