Count the number of triangles in the picture below:

Do you know who was buried in John's tomb?

The doctor advised his patient to take a tablet after every fifteen minutes. He gave him five tablets in total.

How much time will he take to have all the five tablets?

There is one four-digit whole number n, such that the last four digits of n2 are the original number n

The following sentence is false. The preceding sentence is true.
Are these two sentences true or false?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

You know three triplets: Frank John and Wayne (need to return your money). Frank always tells the truth while John and Wayne always lie. You meet one of them on the road and can ask him a three-word question.
Which question, will you ask?

While handling a project, the landscaper is asked by the owner of the mansion that he wants four trees in front of his mansion that are exactly equidistant from each other.

How will he do it?

10 people came into a hotel with 9 rooms and each guest wanted his own room. The bellboy solved this problem.
He asked the tenth guest to wait for a little with the first guest in room number 1. So in the first room, there were two people. The bellboy took the third guest to room number 2, the fourth to number 3, ..., and the ninth guest to room number 8. Then he returned to room number 1 and took the tenth guest to room number 9, still vacant.
How can everybody have his own room?

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