What has no start, end, or centre?

While going to your grandmother's house, you counted Twenty houses on the right side. While returning back to your home, you counted Twenty houses on the left side.

How many houses are there between your home and your grandmother's home?

Can you find out the remainder when 3^300 is divided by 5?

In a science lab, a petri dish hosts a healthy colony of yeast for an experiment. Now every minute, all the yeast cells divide into two. At noon, there was just a single cell of yeast and at 1:22, the Petri dish was half full. Can you calculate when the dish will be full of yeast?

2 ladies and 2 girls need to cross a river in a boat big enough for 1 LADY or 2 girls. How do they do it?

There was a strange boy who was born before his father. How can this be possible?

I am thinking of a five-digit number such that:
The first and last digits are the same, their submission is an even number and multiplication is an odd number and is equal to the fourth number. Subtract five from it and we obtain the second number. Then divide into exact halves and we get the 3rd number.

What number I am thinking of?

Why is the Hole below a Lock?

You board a train. The train will have to enter a tunnel soon. You are claustrophobic. Which place is the best for you to sit?

The measurement of time, That can't be found on a clock, But can be looked upon on a map.

Who is He ?