Solution:

The two statements have given it out. If you read carefully, you will easily be able to deduce the answer.

We know that everybody is wearing a different color than their names. Now let us begin with the man who noticed the first i.e. Mr. Grey. He is wearing either Pink or Orange. But in the second statement, we already know that the person who is wearing Pink is somebody else. Thus Mr. Grey must be wearing a Orange shirt.

Mr. Pink cannot wear Pink shirt and Orange shirt has already been taken, thus he must be wearing a Grey shirt.

This leaves only one choice for Mr. Orange and he must be wearing a Pink shirt.

Solution:

Playing chess

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

Solution:

Yes it is possible in Roman Numerals. In Roman Numerals,
9 = IX
10 = X
11 = XI

Thus by removing one from 9, you are getting 10 and by removing one from 11, you are getting 10 again.

Solution:

Michelangelo juggles the diamonds across while crossing the bridge.

Solution:

Can be found on the pic below.

Solution:

For this answer is 3^0, 3^1, 3^2... That is 1,3,9,27,81,243 and 729.

Solution:

192

Explanation:
I started with the number 192.
Adding the reversed 291 to 192 gave me 483.
Similarly,
483 + 384 = 867
867 + 768 = 1635
1635 + 5361 = 6996

Solution:

There is a simple logic to solve this question.
The size of the chocolate is 2 x 8. Thus, you need to have 2 x 8 = 16 pieces.
Every time you break the chocolate, you will get one extra piece.
Thus, to get 16 pieces, you must break it (16 - 1) = 15 times.

Solution:

There are 3 fruits (1 grapes, 1 apples, and 1 oranges).

Solution:

Both will rotate at Same speed.

Explanation:
Gears of the same size will always rotate at constant speeds despite any smaller or larger gears in between them.

Solution:

TIF56

Explanation:
The password is formed as:
T (5th letter of Shruti)
I (5th letter of Arshika)
F(1st letter of Friday)
5(5th day of week)
6(Length of Friday)

Similarly, we will pick the 1st letter for Monday and 3rd letter for Wednesday.