Solution:

Double or nothing

Solution:

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

Solution:

On the back, since bullet train is accelerating, therefore,the person at the back will spend less time than one in front.

Solution:

2003.

Explanation:
Its a series of prime numbes.

Solution:

Fred Odea won.

Just look at the announcement lines. The first sentence in 'Ok now everybody!' If you take out just the first letter of every word, it will form 'ONE'. In the same manner the second sentence 'The winner of…..' will give form 'TWO' and the third sentence 'The Hardest Riddle Ever Event.' Will form THREE.

Thus the final sentence must form FOUR. There is only one candidate who can suffice with the first two letter and he is Fred Odea. The final sentence of the mastermind must be, 'Fred Odea: Ultimate Riddler!'

Solution:

There are three roses and four bees.

Solution:

The Password.

Explanation:
Clues 2 and 5 are correct and rest are lies.

Solution:

7 Races.

Solution:

2 minutes (duration between 9:59 and 10:01)

Solution:

The attached picture gives away the solution. If you can find another solution, do send us yours.

Solution:

You can ask this question to any one person, "if I ask the man who is next you: which is the correct way and the road to the village, what would the person next to you answer?"
If you happened to ask this question to the liar, he will show you the wrong way.
And if you happened to ask this question to the one who says truth, he will also show you the wrong way.
Once you are done with this, take the other way. This will lead you to the village