Solution:

What.

It is clearly mentioned that "What is the name of the fourth son". Note it's a statement with a period(.) and not with a question mark(?).

Most of the people has given the answer as "East" or "Someone".

Solution:

The Girl

Solution:

Ground Floor.

Any person staying on the floor other than the ground floor would have to call the elevator to reach their respective floors. So, the ground floor calls the elevator way above the individual floors.

Solution:

The kids have 4 slices of pizza in their hands but only three pieces are missing from the pizza box.

Solution:

1600

To calculate the entry fee for someone from Britain, we need to count the number of vowels and consonants in the country name and use the given formula.

Country: Britain

Vowels: 2 (i, a)
Consonants: 5 (b, r, t, n)

Using the formula where vowels are worth $300 and consonants are worth $200, the entry fee for someone from Britain would be:

(2 x $300 + 5 x $200) = $600 + $1000 = $1600

So, the entry fee for someone from Britain is $1,600.

Solution:

The thief turned out to be Anthony, who cunningly concealed the watch inside a bucket.

Solution:

The boy on the right is the one. The piece of his shirt is with the deceased girl, as indicated.

Solution:

He should shoot at the ground.

If Kangwa shoots the ground, it is Rafael's turn. Rafael would rather shoot at Ferdinand than Kangwa, because he is better.
If Rafael kills Ferdinand, it is just Kangwa and Rafael left, giving Kangwa a fair chance of winning.
If Rafael does not kill Ferdinand, it is Ferdinand's turn. He would rather shoot at Rafael and will definitely kill him. Even though it is now Kangwa against Ferdinand, Kangwa has a better chance of winning than before.

Solution:

17 mins

The initial solution most people will think of is to use the fastest person as an usher to guide everyone across. How long would that take? 10 + 1 + 7 + 1 + 2 = 21 mins. Is that it? No. That would make this question too simple even as a warm up question.

Let’s brainstorm a little further. To reduce the amount of time, we should find a way for 10 and 7 to go together. If they cross together, then we need one of them to come back to get the others. That would not be ideal. How do we get around that? Maybe we can have 1 waiting on the other side to bring the torch back. Ahaa, we are getting closer. The fastest way to get 1 across and be back is to use 2 to usher 1 across. So let’s put all this together.

1 and 2 go cross
2 comes back
7 and 10 go across
1 comes back
1 and 2 go across (done)

Total time = 2 + 2 + 10 + 1 + 2 = 17 mins

Solution:

For this answer is 3^0, 3^1, 3^2... That is 1,3,9,27,81,243 and 729.