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

There was a man he lives in a hotel each morning he presses the first floor button each evening if there is a person in the elevator he asks him to press the 10 floor button if there is no one in the elevator he takes the stairs why.

Three doctors said that Bill was their brother. Bill says he has no brothers. How many brothers does Bill actually have?

Decode below three cipher riddles:

26 L of the A
7 D of the W
1000 Y in a M

How can you take 2 from 5 and leave 4?

A police officer was passing by when he saw a guy hiding. He walked up to him and genially asked, "What is your name?"

"Shut up!" the boy responded.

"Where are your manners?" asked the outraged police officer.

"Up that tree," said the boy discourteously, directing to a neighbouring tree.

You're looking for trouble, aren't you?" said the police officer.

"No, trouble is looking for me!" the boy answered solemnly.

Why is the boy behaving like this?

Given that

(78)^9 = 6
And (69)^4 = 11

Can you find out

(99)^2 =?

(Note: This is Logical, not Mathematical)

When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

You knock a Table over in the library, and suddenly 20 eyes are looking at you.

Can you count the number of lines in the below picture?