Replace the question mark with the correct number.

A swan sits at the center of a perfectly circular lake. At an edge of the lake stands a ravenous monster waiting to devour the swan. The monster can not enter the water, but it will run around the circumference of the lake to try to catch the swan as soon as it reaches the shore. The monster moves at 4 times the speed of the swan, and it will always move in the direction along the shore that brings it closer to the swan the quickest. Both the swan and the the monster can change directions in an instant.
The swan knows that if it can reach the lake's shore without the monster right on top of it, it can instantly escape into the surrounding forest.

How can the swan successfully escape?

You have 10 balls with you. A friend of yours out of nowhere asks you to place those ten balls in five lines such that each of the lines has exactly 4 balls on them. He needs to check your intelligence. Prove him by doing the task.

I am a white box having no key or lid.
Yet there is a golden treasure inside it.

What Am I?

What is the riddle which can be asked all day with a different correct answer each time.

Identify the movie name through below Rebus containing Pi Mouse and coconut tree..

Can you tell a 3D object that has just two surfaces?

Look at the below sequence of letters and tell us what the next letter should be:

O T T F F S S ?

A bomb exploded in a room full of married couples and no one died. How?

Solve the following series:
AZ, GT, MN, __, YB