What number should come in place of the question mark below?

Move three sticks of the spiral below to form a square.

In the picture given below, can you find out which digit will take place of the question mark?

If you drop me I’m sure to crack, but give me a smile and I’ll always smile back. What am I?

How can you drop a raw egg from a height onto a concrete floor without cracking it?

How can you make the following equation true by drawing only one straight line: 5+5+5=550 ?

You are an expert on paranormal activity and have been hired to locate a spirit haunting an old resort hotel. Strong signs indicate that the spirit lies behind one of four doors. The inscriptions on each door read as follows:

Door A: It's behind B or C
Door B: Its behind A or D
Door C: It's in here
Door D: It's not in here

Your psychic powers have told you three of the inscriptions are false, and one is true. Behind which door will you find the spirit?

What does this rebus riddle means ?

A 52% bias toss for head using the 51% tail bias coin was done to obtain a fair result.

Can you find how bias is the floor in this case?

Three ants are sitting at the three corners of an equilateral triangle. Each ant starts randomly picks a direction and starts to move along the edge of the triangle. What is the probability that none of the ants collide?