What is at the end of a rainbow?

What's the only room from which no one can enter or leave

What goes up but never comes down?

In front of you, there are 9 coins. They all look absolutely identical, but one of the coins is fake. However, you know that the fake coin is lighter than the rest, and in front of you is a balance scale. What is the least number of weightings you can use to find the counterfeit coin?

I have a head like a cat and feet like a cat, but I am not a cat. What am I?

Solve the counting riddle by identifying the number of triangles in the given picture.

A King wants to send the diamond ring to his girlfriend securely. He got multiple locks and their corresponding keys. His girlfriend does not have any keys to these locks and if he sends the key without a lock, the key can be copied in the way. How can King send the ring to his girlfriend securely?

Two guards were on duty outside a barracks. One faced up the road to watch for anyone approaching from the North. The other looked down the road to see if anyone approached from the South. Suddenly one of them said to the other, "Why are you smiling?"

How did he know his companion was smiling?

Rectify the following equality 101 - 102 = 1 by moving just one digit.

Can you find out a way through which you can make five squares out of the given figure by moving just six match sticks?