Rearrange the letters in "new door" to make one word.

A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.

What is more useful when it is broken?

In a science lab, a petri dish hosts a healthy colony of yeast for an experiment. Now every minute, all the yeast cells divide into two. At noon, there was just a single cell of yeast and at 1:22, the Petri dish was half full. Can you calculate when the dish will be full of yeast?

I have a mouth but I don't eat.
I have a bank but have no money.
I have a bed but i dont sleep.
I wave but have no hands.

Who Am I ?

You need to arrange three 7 and mathematical symbols to form number 1?

Can you make numbers like 24, using numbers 3,3,7 & 7 with any arithmetic operator?

I am an odd number. Take away a letter and I become even. What number am I?

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

A King wants to send the diamond ring to his girlfriend securely. He got multiple locks and their corresponding keys. His girlfriend does not have any keys to these locks and if he sends the key without a lock, the key can be copied in the way. How can King send the ring to his girlfriend securely?