What is more useful when it is broken?

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?

When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

Write the next letter in this sequence.
O, T, T, F, F, S, S, E, __
**Hint: It is a Number Series Puzzle

Four children having five rocks each were playing a game in which they had to throw the rock at a particular solid area in the water. Child 1- Succeeded in throwing three rocks at a solid area but one of the rocks sunk. Child 3 - His aim was so bad that all rocks got sunk. Child 4- He was awesome and none of the rocks got sunk. Child 2 - Was the winner but was struck by a rock in the head and died. Who killed Child 2?

What is next number in the pattern below:

131 517 192 123 ?

I have teeth but i don't bite. Who Am I ?

When my father was 31 I was 8. Now he is twice as old as me. How old am I?

I throw two dice simultaneously.

What is the probability of getting a sum as 9 of the two numbers shown?

What kind of storm is always in a rush?