I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

On 26-01-2022, Juli was murdered at her house in a city in India in the afternoon. There were three suspects in the murder and the following are the statements that were given by them:

John: I visited my village that day.
Jacob: I was out to deposit my house tax in the municipality office at that time.
Jonny: I was at a friend's place having lunch at that time.

Can you find out who is the murderer?

A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.

As easy as you can get into me, it is as hard to get out of me.

Do you know what I am?

There are forty elephants and they have forty-fore heads. How can this be possible?

How many people must be gathered together in a room, before you can be certain that there is a greater than 50/50 chance that at least two of them have the same birthday?

You have two jars of chocolates labelled as P and Q. If you move one chocolate from P to Q, the number of chocolates on B will become twice the number of chocolates in A. If you move one chocolate from Q to P, the number of chocolates in both the jars will become equal.

Can you find out how many chocolates are there in P and Q respectively?

If you drop me I’m sure to crack, but give me a smile and I’ll always smile back. What am I?

When is the top of a mountain similar to a savings account?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?