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

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

What number does the below three word/phrase identify and why?
1. Deck
2. Year
3. Singing in the Rain

Find out a multi-digit number that if multiplied by the number 9 or any of its multiplications products (i.e. 18, 27, 36, 45,..) will result in the multiplication factor repeated (n) number of times.

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?

Detective Rockford was jogging near the beach at 4:30 am.
He hears a sound near the shack "No Michael, Please Do not shoot me".
Next instance he heard the sound of gunfire. Rockford rushes to the shack where he finds women lying dead and a gun in close proximity of three "Doctore Lawyer and a Teacher".

Rockford immediately knew that the Lawyer has committed the crime. How?

While going to your grandmother's house, you counted Twenty houses on the right side. While returning back to your home, you counted Twenty houses on the left side.

How many houses are there between your home and your grandmother's home?

Buy me, smell me or deliver me, I do not change.

Who am I?

How can you write nineteen in a manner that if we take out one, it becomes twenty?

Below is the sum of symbols in each row and column in the figure. Analyzing the figure, can you find out the value of the symbols?