Let Speed of the man is x kmph.
Distance covered in 10 minutes at 20 kmph = distance covered in 8 minutes at (20+x) kmph.
Or, 20 *10
Or, 200 = 160+8x
Or, 8x = 40
Hence, x = 5kmph.
A = Bus Terminal.
B = Let meeting point of first bus and the man and this distance is covered by Bus in 10 minutes. I.e. Distance A to be is covered first bus in 10 min.
As AB distance can be covered by second bus in 10 minutes as well.
Distance Covered by Bus in 10 min = AB = (20
) * 10 = 10
Now, M is the Meeting Point of Second Bus with Man. Man covered distance B to M in 8 minutes.
Now, Relative distance of both Man and Bus will be same as both are traveling in opposite direction of each other. Let Speed of the man = x kmph.
Relative speed = 20 + x
To meet at Point M, bus and Man has covered the distance (AB) in 8 minutes with relative speed. And Same AB distance is covered by bus in 10 minutes. Thus,
Distance covered in 8 minutes with relative speed (20 +x) kmph = distance covered by bus in 10 minuted with speed 20 kmph.