A student reaches the bus station at speed of 8 km/hr on the cycle, boards the bus to the B point whose speed is 15 km/hr. From B to the rickshaw stand he gets a lift from the bike which travels at speed of 20 km/hr. From the rickshaw stand to the exam center he travels at speed of 12 km/hr. If the distance between home to the bus station, bus station to B, B to rickshaw stand, Rickshaw stand to exam center is equal then find student’s average speed. (Approximate values whenever felt necessary)