What Adam and Eve do not have but the rest of the people have?

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

How many letters are in the alphabet?

What is black when you buy it, red when you use it, and gray when you throw it away?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

If two's company, and three's a crowd, then whats four and five ?

John killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

A detective visits his friend John just to discover that John's neighbour Dr Jacob was murdered. Dr Jacob, who is a mathematician wrote the murderer's name in a code word "Hcqtfz". There were five suspects
1. Ajit
2. Pankaj
3. Ganpat
4. Deenu
5. Hariya

The Detective was instantly able to find the murderer.
Can you?

I purchased an awesome ice cream cone having 5 different flavour scoops.
Five flavours are pistachio, mint-chip, strawberry, marshmallow, and raspberry

I will give u some clues so that you can figure out the order of flavours from bottom to top.
1. The bottom flavour of the cone has 10 letters.
2. The marshmallow scoop is between the pistachio and the mint-chip scoop.
3. marshmallow is the raspberry scoop but below the mint-chip scoop.

So can you figure out the flavour of ice cream in order from bottom to top?

What is the difference between a jeweller and a jailer?