A man completed a certain distance by car.He covered 40% of distance at the speed of 50 km/hr, he cover 20% of remaining distance at the speed of 60 km/hr and he cover remaining distance in 6 hours. What is the average speed of man for whole journey ?

Let total distance = D. First leg: 0.4D at 50 km/hr takes 0.008D hours. Remaining: 0.6D. Second leg: 0.2×0.6D = 0.12D at 60 km/hr takes 0.002D hours. Final leg: 0.48D in 6 hours means 0.48D = 6 × 60 = 360 km, so D = 750 km. Total distance = 750 km, total time = 6 + 6 + 6 = 12 hours. Average speed = 750/12 = 62.5 km/hr. Option A (65.5) is incorrect. Option B (44) is incorrect. Option C (60.5) is incorrect.