Here there are 6 teams .
Out of this only 4 teams wins.
ie
total number of orders= 6P4=360
n(S)= 360
(1) For ABCD to come in order, there is only one possibility ,
ie n(L) = 1
there for probability of A,B,C,D finish first, second, third and fourth respectively= n(S)/n(L)
= 1/360
(2) probability that A,B,C and D are first four to finish
lets write the sample set for this
M= ABCD, ABDC,ACBD,ACDB,ADBC,ADCB,
Here with A as first letter we could write 6 outcomes. Simillarly with BCD there are 6 outcomes each,
total number of such outcomes= 6*4=24
therefor probability that A,B,C and D are first four to finish = 24/360
=1/15