Find the next number in the series below

21 32 54 87 131 ?

How do you go from 98 to 720 using just one letter?

Sherlock Holmes was challenged to make a pre-drawn line smaller without erasing it. He did it in fractions of seconds. How?

How can you throw a ball as hard as you can and have it come back to you even if it doesn't hit anything there is nothing attached to it and no one else catches or throws it.

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

Who has married many women but was never married?

You are stuck on an island where you have nothing. You find four pieces of paper somewhere on the island. What will be your strategy to escape from the island safely?

PS: No other resource is available to you on the island, neither can you build anything.

I can sizzle like bacon,
I am made with an egg,
I have plenty of backbone, but lack a good leg,
I peel layers like onions, but still remain whole,
I can be long, like a flagpole, yet fit in a hole.

What has one letter and starts with an E?

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?