Can you replace the question mark with the correct number?

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

A tree doubled in height each year until it reached its maximum height over the course of ten years. How many years did it take for the tree to reach half its maximum height?

What is the word or phrase?

John and Jill are madly in love with each other. To remind Jill of his pure love, John wants to send her a ring by post but in their country where burglary is quite prominent, any package that is not locked comes under the risk of being stolen for the contents.

John and Jill possess many padlocks but neither one of them has the other key.

Can you find a way John can send the ring to Jill safely?

Where do fish keep their money?

I want to fill my bucket using both cold and hot water.
I have two taps for both cold and hot water. The hot water tap fills the bucket in exact 6 hours and the cold water tap fills the bucket in exact 4 hours.
I turn both of them simultaneously but I forgot to turn off another tap which removes the water out of the bucket. This tap can empty the bucket in 12 hours.

How Long will it take to fill the bucket?

Divide 110 into two parts so that one will be 150 per cent of the other. What are the 2 numbers?

How far can you walk into the woods?

There are three cows, two dogs, and one cat: How many legs do you have?