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

In the given figure, move three matchsticks so that the resulting figure contains two rectangles.

Why is it very easy to weigh a fish?

How many sides does a circle have?

Eight Chelsea player makes the following statements :

1. Seven of us are lying here.
2. Six of us are lying here.
3. Five of us are lying here.
4. Five of us are lying here.
5. Four of us are lying here.
6. Three of us are lying here.
7. My name is Torres.
8. My name is Lampard.

The last two are Lampard and Torres or maybe Torres and Lampard.
So can you deduce which of the last two is Lampard or Torres?

What does the following represent?

N N N N N N N

A A A A A A A

C C C C C C C

2 ladies and 2 girls need to cross a river in a boat big enough for 1 LADY or 2 girls. How do they do it?

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?

Replace the question mark with the correct number in the below-given picture?

In the image given, you can find several triangles. Can you count them all?