Which is the smallest number that you can write using all the vowels exactly once?

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

What is the centre of gravity?

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

Who can jump higher than a Mountain?

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?

What does this Rebus Picture mean?

Two fathers and two sons decided to go to a shop and buy some sweets upon reaching. Each of them bought 1 kg of sweet. All of them returned home after some time and found out that they had 3kg of sweets with them.

They did not eat the sweets in the way, nor threw or lose anything. Then, how can this be possible?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see? What is it?