AMC 8 2012 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? $\textbf{(A)}\hspace{.05in}5\sqrt2 \textbf{(B)}\hspace{.05in}10 \textbf{(C)}\hspace{.05in}10\sqrt2 \textbf{(D)}\hspace{.05in}50 \textbf{(E)}\hspace{.05in}50\sqrt2$