Solution:

It is one of the classic riddles. Just be careful how you are adding and you will find out.

Your mother gave you Dollar 300 and you gave her back Dollar 3. So in original, she spent just Dollar 297 on the goods. Out of those Dollar 297, Dollar 295 are with the shopkeeper and Dollar 2 were spent by you on candies.

Solution:

Playing chess

Game needs two players so Brother-8 is playing chess with Brother-2

Solution:

41312432

Solution:

Selfie
Explanation:
: Selfie = is six letter word
: Self = The first four letter is me.
: e = The second and last letter are the same.
: fee = The fourth second and last letter are payment.

Solution:

Can be found on the pic below.

Solution:

fIvE thOUsAnd(5000)

Solution:

Old password : altered

New Password : distinct

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:

16

Explanation:
9 [1x1] squares
5 [2x2] squares
1 [4x4] square
1 [4x4] square

9 + 5 + 1 + 1 = 16 squares.

Solution:

Since the door is not visible in this picture, the bus is moving in the left direction.

Solution:

Isaac Newton picks up a piece of wood and lights it from the fire on the west end of the island.

He then quickly carries it near the east end of he island and starts a new fire. The wind will cause that fire to burn out the eastern end and he can then shelter in the burnt area.

(Funny Part : Isaac Newton survives the fire, but dies of starvation, with all the food in the forest burnt )