Question

Ten married couples are seated randomly in a circle. Find the expected number of wives sitting next to their husbands.

a) 0
b) 1
c) 2
d) 3

Answer 1

The expected number of wives sitting next to their husbands in a circle of ten married couples is 1.

Step-by-step explanation:

To find the expected number of wives sitting next to their husbands, we can consider the probability that each wife is sitting next to her husband. Since there are 10 couples, there are 20 people in total. The probability that a wife is sitting next to her husband is 1/20 (since each person has 1 neighbor out of the 20). Therefore, on average, we can expect 1 wife to be sitting next to her husband. Hence, the answer is b) 1.