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:

9

Explanation:
2 < 3 < 5
To find out the required number of candies, take one in place of the least number (i.e. take one mango candy) and then add all the greater numbers (i.e. three strawberry and five pineapple candies) to it.

Required number of balls = 1 + 3 + 5 = 9.

Solution:

A
D
C
A
B

Solution:

The answer is very simple. All she had to do is take the fifteen cards from the top and reverse them. This would make another pile out of that and there will be two piles - one of 15 cards and one of 37 cards. Also both of them will have the same number of inverted cards.

Just think about it and if the mathematical explanation will help you understand better, here it is.
Assume that there were p inverted cards initially in the top 15 cards. Then the remaining 37 cards will hold 15-p inverted cards.
Now when she reverses the 15 cards on the top, the number of inverted cards will become 15-p and thus the number of inverted cards in both of the piles will become same.

Solution:

457730 * 4 = 1830920
(DOLLAR * 4 = QUARTER)

Solution:

There are three roses and four bees.

Solution:

The woman started walking across the bridge when the guard was inside the hut. She walked all the time he was inside (5 minutes) and then turned and moved back towards the kingdom. On approaching the kingdom he was asked for papers and since she did not have any, she was sent back.

Solution:

See the colored sticks in the picture. We have moved those sticks in the position given in the second image corresponding with the color.

Solution:

The last marble will be yellow.

Since marbles can only be taken out in pairs and you started off with an odd number of yellows there is always going to be one yellow left over that you'll keep putting back in the box until it's left on it's own.

Solution:

The receptionist was pretty clever she played with the mute button of the phone while talking with her mother. She muted everything except the word emergency, call and help. So while talking, she sounded like 'Emergency… Call… Help' to her mother and thus she called the police.

Solution:

7, 4, 6, 5, 8