Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

I have Rs.50 and I spend it in the way as below.

There are three boxes on a table. One of the box contains Gold and the other two are empty. A printed message contains in each box. One of the message is true and the other two are lies.

The first box says "The Gold is not here".

The Second box says "The Gold is not here".

The Third box says "The Gold is in the Second box".

Which box has the Gold?

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.

Can you count the number of blocks in the picture below?

Before the start of the car race, John and Jacob have the same amount of fuel in their car. With this fuel, John can drive for 4 hours while Jacob can drive five hours.
After a time they realize that the amount of fuel left in John's car is 1/4th of the fuel in Jacob's.

For how long they are racing?

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.

I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?

Solve the equation in the image by looking at the pattern closely.

Decode the below four famous ciphers:

8P of the SS
1M of the E
1S of the SS
60M in 1H