1. ## Probability Theory

Hey guys I need some help with this problem-
What is the probability of these events when we randomly select a permutation of {1,2,3,4}?
c)4 precedes 1 and 4 precedes 2
d)4 precedes 1, 4 precedes 2, 4 precedes 3
e)4 precedes 3 and 2 precedes 1

I got (a) and (b) which were (a)1 precedes 4 =12/24 (b) is the same as (a) since it is just in reverse. But I don't understand how to get the others. Thanks for any help.

2. Originally Posted by VGDude85
Hey guys I need some help with this problem-
What is the probability of these events when we randomly select a permutation of {1,2,3,4}?
c)4 precedes 1 and 4 precedes 2
d)4 precedes 1, 4 precedes 2, 4 precedes 3
e)4 precedes 3 and 2 precedes 1

I got (a) and (b) which were (a)1 precedes 4 =12/24 (b) is the same as (a) since it is just in reverse. But I don't understand how to get the others. Thanks for any help.
c) The permutations that satisfy the given conditions are of the form:

4 X X X
3 4 X X

How many of each form can you have ....?

Apply similar logic to the remaining two questions.