During which month do people sleep the least?

Eight of us go fourth, not back, to protect our king from an attack. What are we?

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?

John said, "If yesterday was tomorrow, today would be Friday."

When did John make this statement?

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

John and Jenni are a married couple. They have two kids, one of them is a girl. Assume safely that the probability of each gender is 1/2.
What is the probability that the other kid is also a girl?

Hint: It is not 1/2 as you would first think.

Look at the picture and find out which square is not linked with any of the other squares.

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

You can hear me, but you can't touch or see me.

What am I?

A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.