Given a triangle PQR, A, B, and C are midpoints of the sides of triangle PQR, and M, N, and O are the midpoints of the sides of triangle ABC. The interiors of triangle PAB, triangle AQC, triangle BCR, and triangle MNO are shaded. What fraction of the interior of triangle PQR is shaded?

I don't know how/why the answer would be 13/16?