The vector PQ is Q-P = (2, 1). The vector SR is R-S = (2, 2). One is not a multiple of the others, so the vectors are not parallel. In a parallelogram, these vectors would be identical. PQRS is not a parallelogram.
If each runner must run 1/16 of 1/4 mile then you need 4 runners because four runners makes 4/16 points. this number is equivalent to 1/4 which proves this statement true