Solution:

15/4 hours

Explanation:
Let us say they drive for "t" hours and initial fuel is "f"
Amount of fuel consumed by Fernando car is ft/4
Amount of fuel consumed by Sebastian car is ft/5

As per given condition,
f - ft/5 = 4(f-ft/4)
t = 15/4 hours

Solution:

One Minute building

building 62 => Sixty second building => One minute building

Solution:

The remaining time is 15 minutes.

Since, 1/5 part of the time you have spent is left, the total time is 6 parts.

The total time is 90 minutes. 1/6 of 90 = 15.

Therefore, 15 minutes are remaining.

Solution:

The police officer knows the story was not true since Vasco was shot from back and he was injured only in the stomach.

Solution:

Mr. Orange is wearing a Green shirt.
Mr. Pink is wearing an Orange shirt.
Mr. Green is wearing a Pink shirt.

One should notice that the person wearing Green shirt agreed to Mr. Pink's statement which implies that Mr. Pink is not wearing Green. Obviously, he cannot be wearing a Pink shirt which is why he must be wearing an Orange shirt.

Now, we can easily deduce that the Green shirt is being worn by Mr. Orange and the Pink shirt by Mr. Green since they must be wearing a color different than their names.

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:

It was easy as it was daytime. They did not need headlights or the light on the number plate.

Solution:

4 6 5 3 (from magician perspective)
3 5 6 4 (viewer perspective)

Detail:

From user perspective:
3 5 6 4 => 5 6 4 3 => 6 5 4 3

For magician perspective
3 4 5 6 (ascending order as)

Solution:

He asks, "if the mystical stone is not in the East, I s it in the West?"
Possible reply by Mola Ram
1. Yes: mystical stone is in the west.
2. No: mystical stone is east.
3. I don't know: mystical stone is North.

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.