It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

Two fathers and two sons went fishing one day. They were there the whole day and only caught 3 fish. One father said, that is enough for all of us, we will have one each. How can this be possible?

What does the following represent?

N N N N N N N

A A A A A A A

C C C C C C C

There are three boxes of different sizes with three cupcakes inside each of the boxes in Christina's kitchen. At night her daughter wakes up and goes to the kitchen. She opens a box and eats all three cakes.

But in the morning Christina finds out that each box still had three cupcakes. How?

Can you find out which number multiplied by itself will give the output as 12345678987654321?

A shepherd had 18 sheep, out of which, all but ten died.

Can you tell us how many sheep was he left with?

John drives to his office at 20km/hr. After reaching the office, he realizes that today is a holiday. He went back at an average speed of 30km/hr. Discounting the time spent in the stoppage what was the average speed of his journey?

Things are just as they seem, right? Well, check again.
Can you count the number of tigers in this picture ?

Mr Red Lives in the red house.
Mr Green Lives in the greenhouse.
Mr Yellow Lives in the yellow house.

Who lives in the Whitehouse?

Open a Laptop which is password protected. Hint for the password is given as below:

1 mobile 3 books 2 Boards 1 night 4 balls 2 lighters 1 ghost 1 hat 3 watches