While covering a distance of 24 km, a man notices that after walking for 1 hour
Answer: (2) 6 km/hr
Let the speed be x km/hr.
Then, distance covered in 1 hr: 40 min
1 2/3 hrs = 5x/3 km.
Remaining distance = [24-5x/3] km.
Therefore, 5x/3 = 5/7[24-5x/3] ⇔ 5x/3 = 5/7[72-5x/3] ⇔ 7x = 72-5x
= 12x = 72
=> x = 6
Hence, speed = 6 km/hr = [6x 5/18] m/sec = 5/3m/sec = 1 2/3 m/sec
3. If a man walks at athe rate of 5 kmph, he misses a train by 7 minutes. However, if he walks at the rate of 6 kmph, he reaches the station 5 minutes before the arrival of the train. Find the distance covered by him to reach the station.
Sol. Let the required distance be x km.
Difference in the times taken at two speeds = 12 min = 1/5 hr.
Therefore, x/5 – x/6 = 1/5 => 6x – 5x = 6
=> x = 6.
Then, the required distance is 6 km/hr.
Hence, the correct answer is option (2) 6 km/hr.