Can you find a pattern and the missing number in the series given below?

100, 155, 258,? , 584, 819.

What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

A mathematician couple was having a Frappuccino in Starbucks sitting opposite to each other. Suddenly the guy noticed the text written on the paper in front of them and exclaimed that it was wrong. The girl denied it and said it is appropriate. Both are correct. What is written on the paper?

I have feet, but no legs. Which animal Am I?

In the following series, a set of numbers is progressing with a particular pattern. Can you deduce that pattern and find the missing set?

(2 + 6), (21 + 6), (58 + 6), (119 + 6), ___

You have a roll of cloth 1km long. You have a machine which cuts this roll into pieces of 10-meter-long cloth.

How long would it take for the machine to cut the roll if each cut took 4 secs?

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

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 make a loud sound when I’m changing. When I do change, I get bigger but weigh less. What am I?

What is the word or phrase?