I have a problem with understanding some of my statistics homework. I hope that some of you could help me understand.
In summary the question is as follows:
There are 30 people in a group, which are split up in 2 groups of 15. The first group we call group1 and the other group2. Group1 has been placed in an order from 1 till 15 and group 2 is ordered 16 till 30. In the question we need to find two persons. We do this by removing each time the 3rd person till we only have 2 people left.
So for example:
1 2 3 4 5 6 7 8 9 10 11.. 30; We start with number 4, first number 7 will be removed. Then number 10 will be removed. Next will be number 13. Etc, And after number 28 number 1 will be removed. till there are only 2 people left.
The start position is random, so it could be 1 till 30.
I need to answer the following questions:
- What is the probability that there are 0 persons left from group1?
- What is the probability that there is 1 person left from group1?
- What is the probability that the two persons, who are still there are both from group1?
Someone told me the answers, but I do not understand them. So I hope that someone could explain it to me. I got the following answers: