If 21x = 79x, what is the value of x?

Which is Odd One Out and why?

4377

3954

9862

8454

9831

Make eight squares by moving only two matchsticks.
Note- Square can be of different sizes.

If two fifty-foot ropes are suspended from a forty-foot ceiling that is twenty feet apart, how much rope will you be able to steal if you have a knife?

Can anyone tell me a word in the English dictionary which has a silent 'z'?

Can you name an animal whose killing cannot be performed without spilling your own blood?

Spelt forwards I’m what you do every day, spelled backwards I’m something you hate. What am I?

You are confined in a room and given two metal rods. Out of these two rods, one is magnet and the other is the iron rod. They look starkly similar. You don't have any other metal object in the room.

How will you decide which one of those is magnet?

A woman is sitting in her hotel room and hears a knock at the door. She opens the door to see a man whom she’s never met before. He says, “I’m sorry, I have made a mistake, I thought this was my room.” He then goes down the corridor and into the elevator. The woman goes back into her room and calls security. What made the woman so suspicious of the man?

You can see it everyday, But cannot touch it at will. What is it?