Two trains T1 and T2 are travelling on parallel tracks and in opposite directions. P1 and P2 are two persons who are travelling in T1 and T2 respectively. When the two trains just start to cross each other, P1, who is at the tail end of T1, starts running towards the front end of T1, at a speed of 6 m/s, and P2, who is at the front end of T2 starts running towards the tail end of T2 at a speed of 4 m/s. If the lengths of T1 and T2 are 216 m and 432 m respectively, and the speeds of T1 and T2 are 108 km/hr and 144 km/hr respectively in how much time (from the time T1 and T2 start to cross each other) will the two persons cross each other?