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

Replace the question mark with the correct number.

John replied, when asked how old he was. In 2 years he will be twice as old as he was five years ago.' How old is he ?

I make a loud sound when I’m changing. When I do change, I get bigger but weigh less. What am I?

Can you find the dog hidden in a group of pandas?

You are given a cube that is made with the help of 10x10x10 smaller cubes summing up to a total of 1000 smaller cubes. You are asked to take off one layer of the cubes.
How many remain now?

Its something that each of us devours,
Not just us but birds, beats, trees, and flowers,
Frets iron and nibbles steel,
Toil hard stones to meal,
Exterminates king, collapse town,
And blows the mountains down.

In one of the popular batman series movie "Batman Forever", there was a riddle that goes like "Tear me off and then scratch my head and I was red then and now I am back. Who am I?

If you drop a 15 kg iron bar and a 5 kg bag of cotton from a height of 50 meters which will reach the ground first?

By using 'because' continuously three times, can you make an English statement ?