What is the probability of these events when we randomly select a permutation of 1,2,....,n where n>=4
a) 1 precedes 2
I have no idea how to do this one
b) 1 immediately precedes 2
This one is simple I think. I just considered 1 and 2 as one unit to be permuted with the rest of the numbers and I get (n-1)!/n!= 1/n
I could really use some advice, thank you so much!!
no it does not matter what n is. thank you i understand now. I am really having some difficulty with some of these problems.
how about this one:
n precedes 1 and n precedes 2
should this be 1/4 then? (either n precedes 1 or it doesnt and either n precedes 2 or it doesnt)