Solution:

Dice (6 sided)

Explanation:
> I am always 1 to 6: numbers on dice are from 1 to 6.

> I am always 15 to 20: Sum of all the visible sides (1 top and 4 on the sides) always add up to 15 to 20.

> I am always 5: Five sides are visible.

> I am 21 when I am flying: When we throw the dice, we can see all 6 sides for a small moment which all add up to 21.

Solution:

Move and then pour all juice from second glass to fifth glass.

Solution:

Step 5 is invalid, because we are dividing by (x-y), and since x=y, we are thus dividing by 0. This is an invalid mathematical operation (division by 0), and so by not following basic mathematical rules

Solution:

Q = 1
U = 9
I = 6
C = 8
K = 3.

Explanation:
Replace values in( Q + U + I + C + K)^3 = QUICK
(1+9+8+6+3)^3 = 19863
27^3 = 19863
19863 = 19863

Solution:

We now have a square of 3x3 size, 2 squares of 2x2 size and 5 squares of 1x1 size.

Solution:

The Winchester brothers - sam and dean

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:

Upon reaching each room, he found out that the window facing the dead body was closed. He had to open the window himself. This tells that there was somebody else with him who closed the window. If he would have committed suicide, at least one window would have been open.

Solution:

The old lady of course.
After helping the old lady into the car, I give the car keys to my best friend.
And then i go ib the bus with child love <3

Solution:

Everyone will done one day or other.

Abraham Lincoln era is too old and we expect most of them(if not all) to be dead by now.

Solution:

Slumdog Millionare = Slum + Dog + Million + air