Solution:

This is a Perception riddle and hence there is no right or wrong attached to this answer.

It can be considered as a sound
> It makes the sounds of branches snapping and the almighty thump when the trunk hits the hard ground. The sound is sound and doesn't rely on people to interpret it.
> Yes. And isn't that a rather arrogant question, as what about all the animals that presumably hear it?

It cannot be considered as a sound because
> Does it depend on what you mean by 'sound'? The airwaves would still vibrate but without an ear/listening device to receive them, there would be no sound.
> The sound is something within human experience. Outside of this, it's just air (or whatever another medium) vibrating. If someone is there to hear it, it makes a sound, if not, it causes rapid movement of particles.

Solution:

888 + 88 + 8 + 8 + 8 = 1000

Solution:

I am word "Introvert"

Solution:

They used the planks in the manner that is shown in the figure.

Solution:

Karate Kid (car + at + tea + kid)

Solution:

He should shoot at the ground.

If Kangwa shoots the ground, it is Rafael's turn. Rafael would rather shoot at Ferdinand than Kangwa, because he is better.
If Rafael kills Ferdinand, it is just Kangwa and Rafael left, giving Kangwa a fair chance of winning.
If Rafael does not kill Ferdinand, it is Ferdinand's turn. He would rather shoot at Rafael and will definitely kill him. Even though it is now Kangwa against Ferdinand, Kangwa has a better chance of winning than before.

Solution:

2 people

Say 2 helpers are Helper1 & Helper2

Helper1 food Helper2 food McDuck's Food
End of Day 1 : 1 4 4
Now 'A' will head back

End of Day 2 : N/A 2 4
Now 'B' will head back

Now Mr. McDuck have 4 day food :-)

Solution:

Rhea will open just one present.
Cindy|Y - Y is the 25th alphabet
Duk|E - E is the 5th alphabet
Joh|N - N is the fifteenth alphabet
Rhe|A - A is the first alphabet

Solution:

He should draw any chit of paper and before unfolding it, he must eat and swallow the chit. In this manner, to determine the judgment of the god, they will have to look at the other chit which will have 'Guilty' written over it. Thus everyone will believe that the chit which he ate had innocent written over it and thus they will believe that he is innocent.

Solution:

   9567
+ 1085
======
 10652

Solution:

The check was for dollars 31.63.

The bank teller gave her dollars 63.31
She spent .05, and then she had dollars 63.26, which is twice the check.

Let x be the dollars of the check, and y be the cent.

The check was for 100x + y cent
He was given 100y + x cent

Also
100y + x - 5 = 2(100x + y)
Expanding this out and rearranging, we find:
98y = 199x + 5

or 199x ≡ -5 (mod 98)
or 98*2*x + 3x ≡ -5 (mod 98)
3x ≡ -5 ≡ 93 (mod 98)
this quickly leads to x = 31