Solution:

No one can take out any money from the taxi meter because it simply does not contain any money. It just has a timer installed that is used to decide the fare as per the distance covered.

Solution:

2003.

Explanation:
Its a series of prime numbes.

Solution:

Either your read from start or from ends, it will be same

Solution:

7

Explanation:
8th is bald man head, check the video below.

Solution:

Old password : altered

New Password : distinct

Solution:

41312432

Solution:

8/(1−1/5)

Solution:

12 steps:

Steps 11 Liter jug 6 Liter Jug
1. 11 -
2. 5 6
3. 5 0
4. 0 5
5. 11 5
6. 10 6
7. 10 0
8. 4 6
9. 4 0
10. 0 4
11. 11 4
12. 9 6 ==> i found 9 liter in 11liter jug(as required)

Solution:

You will ask, I have a number in my mind that i.e. either 2 or 3. Is the number that I have in my mind smaller or equal to the number that you are thinking of?

If Alan replies with no, he is thinking of the number 1.
If Alan replies with yes, he is thinking of the number 3.
If Alan replies with don't know, he is thinking of the number 2.

Solution:

16-days

In 15-days, he will climb 15-inch and when he climbs 5 inch more, he will be out of the well :-)

Solution:

charles put the ring into the box, secure it with one of your locks, and send the box to the girl firend.
She should then attach one of his own locks and return it. When you receive it again, remove your lock and send it back with her lock. Now she can unlock his own lock and retrieve the object.