What has many keys but can’t open a single lock?

There is a barrel with no lid and some wine in it. 'This barrel of wine is more than half full,' said Curly. 'No it's not,' says Mo. 'It's less than half full.' Without any measuring implements and without removing any wine from the barrel, how can they easily determine who is correct?

You measure my life in hours
I serve you by expiring
I vanish faster when I am thin
and slower when I am thick
The wind is my energy
What am I?

You are a cab driver who pools passengers. You pick 3 people from a destination and drop 1 after an hour. 2 people climb aboard at the same time and you drop 3 at the next destination. After some time, you pick 2 passengers only to drop 1 after a short distance where 3 more passengers climb up the cab. You leave the rest of the passengers one by one to their destination and then come back home.

Can you tell the eye color of the cab driver?

I have no life, but I can die. What am I?

If you read clockwise, you can form a word by inserting three missing letters in the picture given below. Can you do it?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

Replace the question mark with the correct number in the below-given picture?

Can you Find and name the hidden bird in the picture below ?

How can you drop a raw egg from a height onto a concrete floor without cracking it?