If eleven plus two equals one, what does nine plus five equal?

Name the three-letter word that can complete the below words:

A) L O _ _ _ E
B) E D U _ _ _ E
C) _ _ _ E R
D) _ _ _ T L E

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

What can you catch but never throw?

Find the next number in the sequence

1, 2, 6, 21, 88, __?

Count the squares in the matchstick puzzle below?

I am not alive, but I grow; I don't have lungs, but I need air; I don't have a mouth, but water kills me. What am I?

Twenty frogs are sitting on a log floating on the surface of a river. Two of them decide to jump off into the water.

How many frogs are there on the log at this moment?

A man is trapped in a room. The room has only two possible exits doors. Through the first door there is a room constructed from magnifying glass. The blazing hot sun instantly fries anything or anyone that enters. Through the second door there is a fire-breathing dragon. How does the man escape?

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?