We have a Poisson arrival process with constant rate 1, Tndenotes the time of n-th arrival. And N(t) denotes the total # of arrivals happened by time t. Calculate these expressions:

1- E(N(10)N(5)|T2=6)

2- P(T3>5|T2=4)

3- E(N(15) N(3) | N(5) = 3)