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

10 people came into a hotel with 9 rooms and each guest wanted his own room. The bellboy solved this problem.
He asked the tenth guest to wait for a little with the first guest in room number 1. So in the first room, there were two people. The bellboy took the third guest to room number 2, the fourth to number 3, ..., and the ninth guest to room number 8. Then he returned to room number 1 and took the tenth guest to room number 9, still vacant.
How can everybody have his own room?

Okay before we begin with the puzzle, do keep in mind that you have to answer it quickly.

You are participating in a car race. Seeking the perfect moment, you overtake the second person in the race. What positions are you in now?

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

How many times do a clock's hands overlap in a day ?

what one word does the below rebus identifies?

Can you decipher the two rows to find the hidden word?

I cannot talk, but I always reply when spoken to. What am I?

While preparing the table for dinner, wife came up with an idea to tease his mathematician husband. She asked her husband to pick nine toothpicks and make ten without breaking any toothpick.

The husband was also smart and did it within seconds. How ?

What does this mathematical rebus means ?