A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?

You have a basket containing ten apples. You have ten friends, who each desire an apple. You give each of your friends one apple.
Now all your friends have one apple each, yet there is an apple remaining in the basket.
How?

I am lying and I always lie. Tell me whether I am lying or telling the truth.

You need to pick one entry from pot A and one from pot B to have a perfect match. Can you do it?

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?

Find the missing number in the sequence below:

How many times can you subtract the number 5 from 25?

My first is in chocolate but not in ham. My second is in cake and also in jam. My third at tea time is easily found. Altogether, this is a friend who is often around. What is it?

From a pack of 52 cards, I placed 4 cards on the table.

I will give you 4 clues about the cards:

Clue 1: Card on left cannot be greater than the card on the right.
Clue 2: Difference between the 1st card and 3rd card is 8.
Clue 3: There is no card of an ace.
Clue 4: There are no face cards (queen, king, jacks).
Clue 5: Difference between the 2nd card and 4th card is 7.

Identify four cards?

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