Boat 'A' in still water with a speed of 12 km/hr starts from a fixed point in a river. After 't' minutes, boat 'B' left the same point to catch boat 'A'. Both are moving in the upstream direction and the speed of the stream is 2 km/hr. If boat 'B' catches boat 'A' after chasing for 6 km and the still water speed of boat 'B' is 41.66% more than that of the boat 'A' then find the value of 't'?