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

Why do we preferably have round manhole covers and not square ones?

Why do you find that most of the buildings are deprived of the 13th floor?

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

Decode below three cipher riddles:

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

A spy was in Canada trying to steal insider information on how to set up new Maple Syrup factories in their country. He was introduced to the operations manager of the biggest factory in Canada. However, the manager was suspicious and decided to test him with a question before he trusted him. So he asked, “What would you be sure to find in the middle of Toronto?” The spy thought fast and came up with an answer for the manager. What was his answer?

In a certain bank, a man deposits a certain amount. According to the bank policies, the amount will be doubled up in a year but as the service charge, they will also deduct Rs. 65 by the end of every year.

If after the 6th year, the amount becomes 0, what do you think is the original amount he deposited in the bank?

What do you think with the below Picture ?

They are three errirs in this question. Can you find them?

You have two strings whose only known property is that when you light one end of either string it takes exactly one hour to burn. The rate at which the strings will burn is completely random and each string is different.

How do you measure 45 minutes?