Solution:

Let's say the Mice are X and Y and Bottle are B1, B2....B9

Step1:
X drinks B1 B2 & B3
Y drinks B1 B4 & B5

Possible Outcomes
If both mice die, B1 is the poison bottle.
If only mice X dies, Either B2 or B3 is the poison bottle.
If only mice Y dies, Either B4 or B5 is the poison bottle.
If nobody dies, Poison is in B6 B7 B8 or B9


Step2: (If nobody dies)
X drinks B6 B7
Y drinks B6 B8

Possible Outcomes
If both mice die, B6 is the poison bottle.
If only mice X dies, B7 is the poison bottle.
If only mice Y dies, B8 is the poison bottle.
If nobody dies, B9 is the poison bottle.

Step2: (Only X dies - Either B2 or B3 is the poison bottle)
Y drinks B2, if Y dies B2 is the poison bottle else B3

Step2: (Only Y dies - Either B4 or B5 is the poison bottle)
X drinks B4, if X dies B4 is the poison bottle else B5

Solution:

Here is a way to do it. We dont know if it can be done using some other arrangement or not. If you know, do send us.

4 | 3 | 8
9 | 5 | 1
2 | 7 | 6

Solution:

The woman told him to take out one nut each from the rest of the wheels and use them.

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:

Remove the same 2 matchsticks from each figure and move figure towards left 45 degrees, It forms the letters V W X Y.

Solution:

Yes, some people are going get really tiny pieces but you were allowed for that right. Also, there is another way of doing it. Can you think of it?

Solution:

The password is U472BMT.

Read aloud the line and you will sound something like "U Four Seven 2 B M T".

Solution:

There are six unique answers

Ans1:
7 x 4 = 28
36 / 4 = 9
1 + 4 = 5

Ans2:
9 x 4 = 36
28 / 4 = 7
1 + 4 = 5

Ans3:
3 x 8 = 24
56 / 8 = 7
1 + 8 = 9

Ans4:
7 x 8 = 56
24 / 8 = 3
1 + 8 = 9

Ans5:
4 x 8 = 32
56 / 8 = 7
1 + 8 = 9

Ans6:
7 x 8 = 56
32 / 8 = 4
1 + 8 = 9

Solution:

The ball will take infinite bounces before it is stopped. As per the question it will keep on bouncing half way up every time it hits the ground. But gravity will play its part at certain point of time which will make it stop.

Solution:

If you notice the animated gif, you know that D, C and B are going to die. D dies directly after coming in contact with the object, C dies after being thrust by the spikes of the see-saw and B dies with the blue ball.

But consider the situation that the person at E stands for Ebola. Eventually A dies as well.

We thank 9gags for this awesome gif.

Solution:

It can be solved as below.