A man takes total 5 hours to go A to B at 3 km/hr and comes back at 2 km/hr. Find the distance (in km) between A and B.

5 6 7 8

6

When distance is same (A→B, B→A), the ratio of speed and time is reciprocal. Therefore, Distance  = Speed × Time                   (A to B)  = 3(k/h) × 2 (h) = 6 kms.