A man walks at a speed of 3 km/hr and runs at a speed of 7 km/hr. How much time will the man require to cover a distance of 10 1/2 km, if he completes half of the distance, i.e., (5 1/4) km on foot and the other half by running?
Answer: D
Required time = (5 1/4)/3 + (5 1/4)/7 = 2 1/2 hours.