Question

12 people sit in a row in random order. two of the people are a and

b. what is the probability that a and b sit next to each other g

Answer 1

A has a 2 in 12 chance of being at an end and a 10 in 12 chance of being somewhere in the middle. For the end seats, B has a 1 in 11 chance of sitting next to A, and a 2 in 11 chance of being next to A if A's in a non-end seat. (2/12)*(1/11)+(10/12)*(2/11)=2/132+20/132=22/132 chance of being next to each other.