A person walks at a speed of 4 km/hr and runs at a speed of 8 km/hr. How many hours will the person require to cover a distance of 20 km, if the person completes half of the distance by walking and the other half by running?	Pick: A) 2.75 B) 3.25 C) 3.75 D) 4.25 E) 4.75

Rationale: "time = 10 / 4 + 10 / 8 = 30 / 8 = 3.75 hours the answer is c ."
Answer: C