Solution:

2nd

When the cylinder is spun for the first and last time, the following six outcomes are possible:

First:
First chamber is fired first. The first player loses.

Second:
Second chamber is fired first. The first player loses.

Third:
Third chamber is fired first. The first player loses.

Fourth:
Fourth chamber is fired first. The second player loses. (First shot, player 1, chamber 4 empty. Second shot player 2, chamber 5, empty. Third shot player 1, chamber 6 empty. Fourth shot player 2, chamber 1 not empty.)

Fifth:
Fifth chamber is fired first. The first player loses. (First shot, player 1, chamber 5 empty. Second shot player 2, chamber 6, empty. Third shot player 1, chamber 1 not empty.)

Sixth:
Sixth chamber is fired first. The second player loses. (First shot, player 1, chamber 6 empty. Second shot, player 2, chamber 1, not empty)

Thus, if you analyze, you will find that the second player has a 4/6 chance of winning. Therefore if you want to win the game, going second gives you better shot at it.

Solution:

The probability is certain.
The average number of arms is less than 2.

Solution:

If all other conditions are fair, then the toss will generate a 52:48 distribution in the favor of heads. The toss boas factor will then be 52/48.

Using the same approach, if the coin will generate a 49:51 distribution in the favor of tails, the coin bias factor for heads will be 49/51.

Using the results, we can say that the combined bias factor is (52 * 49) / (51 * 48) = 2548 / 2448 which can be canceled if the floor bias factor is 2448 / 2548. The floor will generate a distribution factor of 2448 / (2558 + 2448) : 2548 + 2448) in favor of tails. If you calculate roughly, it will be 51.00080064% tails.

Solution:

Girl

Explanation:
In the House P:
There can be three possibilities.
Older Younger
Boy Girl
Girl Boy
Boy Boy
Since a boy is mentioned, we can't have a Girl-Girl option. Now all these options are equally possible and thus we will take them all into account. Two of the outcome have girls as an option and thus the probability here will be 2/3.

In the House Q:
We know that the elder child is a boy and thus there can be only two possibilities:
Older Younger
Boy Girl
Boy Boy

Here, the probability of having a girl child will be 1/2.

Thus you must choose the house P as we have better probability of having a girl in that house.

Solution:

First Case:
The possible combinations of the adjacent bullets placed in the chambers are:
1, 2
2, 3
3, 4
4, 5
5, 6
6, 1

Now if you don't spin the barrel:
The first shot was empty and thus the combinations of (6, 1) and (1, 2) surely don't have bullets. This means that the bullets are present in some other possible 4 slots.

Therefore P (Death) = 1/4 = 0.25
P (Survival) = 3/4 = 0.75

If you chose to spin the barrel:
P (Death) = 2/6 = 1/3 = 0.33
P (Survival) = 4/6 = 2/3 = 0.77

Therefore you must not ask to spin the barrel and you will have a better chance at surviving.

Second Case:
If you don't spin it:
You were not hit in the first shot. Thus,
P (Death) in second hit = 2/5 = 0.4
P (Survival) in second hit = 3/5 = 0.6

If you spin the barrel
P (death) in the second hit = 2/6 = 1/3 = 0.33
P (Survival) in second hit = 4/6 = 2/3 = 0.77

Thus in this case, you have better survival rate if you chose to spin the barrel.

Solution:

Here, there are two events that are independent of each other. Now, in such case, we calculate the probability of both occurring A and Bas:
P(A and B) = P(A) * P(B)
P(Pink) = 1/5
P(Pink and Pink) = P(Pink) * P(Pink)
= 1/5*1/5
= 1/25

Solution:

50%

Explanation:
When the coins are tossed there can be eight possible outcomes (2*2*2)
HHH
HTT
HTH
HHT
TTT
THH
THT
TTH

If you find out, we have only four favorable outcomes. Also, the events here are independent and thus we can calculate the probability by using these only.

Thus the probability is 50 percent.

Solution:

The chances that the pair you take out is a white pair is zero.

Just analyze the statement carefully. If there are two colored socks in a drawer, there can be three chances if you take out a pair. It can be either black socks or white socks or a mixed of two. But as per the statement the chances of taking out a black pair of socks is 1/2. Therefore, only two chances exist. We do know that there is a mix of white and black socks in the drawer and thus the second chance has to be a mixture of them both. This is the reason why we can deduce that there are three black socks in the drawer and just one white sock. Thus the probability of taking out two white socks will be zero.

Solution:

After analyzing the possibilities, it is obvious that my friend has better chances of winning and his average score will be lower at the end.

Let us assume that we have not completed the sequence yet and understand the possibilities. If the last toss of coin was tails, start with step 1 otherwise start at step 2.

Step 1: If either of us toss the coin to get tails, nothing will change. We both will still be at step one and we both will still be needing three more correct tosses of coin to complete our respective sequences. If we get heads, then we continue.

Step 2: If either of us tosses the coin to get heads, we stay on this very step. If we get tails, we continue.

Step 3a (me): If I tosses the coin to get tails, I will have to go back to the step one again and try till I get heads again. Thus I will need at least 3 more tosses to complete my sequence.

Step 3b (my friend): If my friend tosses the coin to get heads, he will go back to step 2 again and will try till he gets tails. In this scenario, he will need at least 2 more tosses to complete the sequence.

Clearly, he has the better opportunity to win this game.

Solution:

50%

Explanation:
The probability will be 50% only as it always was. The next flip of coin is not dependent on what the results were in the previous flips.