5 persons A, B, C, D and E are in a queue of a shop. The probability that A and E always occur together, is

Five persons A,B,C,D and E are standing in a queue of a ration shop . The probability that A and E are always togethar is .

Eight persons A, B, C, D, E, F, G and H appeared for an inter view. Find the probability that both A and D are selected in the interview?

Five persons A, B, C, D and E are sitting in a row facing you such that D is on the left of C and B is on the right of E. A is on the right of C and B is on the left of D. If E occupies a corner position, then who is sitting in the centre ?

Find the number of ways in which four particular persons A, B, C, D and six more persons can stand in a queue so that A always stands before B, B before and C before D.