Solution:

This is absolutely possible. It happened because only three people went for fishing that day: The son, his father and his grandfather.

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:

That person in the picture is the son of the man holding the picture.

Solution:

Let us denote the four people with A, B, C and D.
A takes 1 minute to cross, B takes 2, C takes 5 and D takes 10.

A and B cross first spending 2 minutes.
A comes back with torch taking 1 minute.
C and D cross taking 10 minutes.
B comes back with torch taking 2 minutes.
Finally, A and B cross the bridge taking 2 minutes.

2 + 1 + 10 + 2 + 2 = 17 minutes

Thus, this is the way they all managed to cross that bridge that night.

Solution:

I have just two tee shirts neither of which are green, blue or orange in color.

Solution:

101

Assuming '?' is no. of runs needed by Ajit in 51st inning.
(50 * 50 + ?)/51 = 51
=>2500 + ? = 51 * 51
=> ? = 2601 - 2500
=> ? = 101 (Answer)

Solution:

Since you can't identify which tablets are meant for which purpose, what you can do is take half of each tablet. In this manner, you will be able to get 1 of each tablet no matter what.

Solution:

The image that we have attached here is self-explanatory. You just have to move four matches and you can obtain this figure.

Solution:

There is only one way to do it. The old man must ask one of his son to divide the land in two parts and then ask the other one to pick up any land he want from the two. In this way, the first son will try to be fair and the second one won't mind as he will get to choose one first.

Solution:

The only possible way to do it is to form an equilateral triangle pyramid and then place the balls at the corners of the figure. Yes, you will have to use 3 dimensional figure.