A prisoner is told: "If you tell a lie, we will hang you and if you tell the truth, we will shoot you." What did the prisoner say to save himself?

A sundial has the fewest moving parts of any timepiece. Which has the most?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see? What is it?

Why is the Hole below a Lock?

Christina, Allison and Lena are 3 daughters of John a well-known Mathematician, When I asked John the age of their daughters. He replied "The current age of her daughters is prime. Also, the difference between their ages is also prime."

How old are the daughters?

What Deficiency does the below rebus represent?

VIT_MIN

Two boys wish to cross a river. The only way to get to the other side is by boat, but that boat can only take one boy at a time. The boat cannot return on its own, there are no ropes or similar tricks, yet both boys manage to cross using the boat.

How?

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

What am I?

I came first on earth but second on the heaven.
I also came twice in a week but found just once in a year.
I stay away from months but you can find me in February.

What am I?

10+10 and 11+11 can give you the same answer.

Explain how?