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

If an earthquake is 1 point higher on the Richter Scale than another earthquake which is actually 10 times stronger, how much stronger would an earthquake be if it was just half a point higher on the Richter scale?

I am quite hot but become too cold if you remove the first two letters. What am I?

Can you tell a 3D object that has just two surfaces?

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?

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

A clock loses 10 minutes each hour. If the clock is set correctly at noon, what time is it when it reads 3 PM?

It's a 7-letter word.
If we remove 1 letter from it, it remains the same.
If we remove 2 letters from it, it remains the same.
If we remove 3 letters from it, it remains the same.
If we remove all the letters from it, still it remains the same.
What is it?

What does the below mathematical rebus mean?

I hide my treasure in the ground, my tail is big and fluffy. If you spot me in a tree, please don’t call me scruffy. What am I?