Why 1729 is a magic number? Answer Logically.

There is a square piece of paper with a hole that is denoted by the circle on the top right side in the given picture. You have to cut the paper in a manner that it forms two and only two separate pieces of paper and then rearrange the pieces in a manner that the holes come in the centre of the paper.

As easy as you can get into me, it is as hard to get out of me.

Do you know what I am?

On my way to St. Ives I saw a man with 7 wives. Each wife had 7 sacks. Each sack had 7 cats. Each cat had 7 kittens. Kittens, cats, sacks, wives. How many were going to St. Ives?

John was piloting a plane behind a car but was never able to overtake it. Why?

It's a protector.
It sits on a bridge.
One individual can see directly through it, while others wonder what it hides.

What is it?

You are mixing a mixture of cement and Sand with five gallons of water. You have a garden hose giving you all the water you need. The problem is that you only have a four-gallon bucket and a seven-gallon bucket and neither has graduation marks. Find a method to measure five gallons.

With the help clues provided in the image, can you find the 5 digit key?

Can you solve the below geography rebus by decoding the below rebus ?

Different lights make me strange by changing me into different sizes. What am I?