Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

Spelt forwards I’m what you do every day, spelled backwards I’m something you hate. What am I?

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

What is the centre of gravity?

I am a word that begins with the letter “i.” If you add the letter “a” to me, I become a new word with a different meaning, but that sounds exactly the same. What word am I?

Two friends were stuck in a cottage. They had nothing to do and thus they started playing cards. Suddenly the power went off and Friend 1 inverted the position of 15 cards in the normal deck of 52 cards and shuffled it. Now he asked Friend 2 to divide the cards into two piles (need not be equal) with equal number of cards facing up. The room was quite dark and Friend 2 could not see the cards. He thinks for a while and then divides the cards in two piles.

On checking, the count of cards facing up is same in both the piles. How could Friend 2 have done it ?

What is the difference between a jeweller and a jailer?

Can you find the company name in the pictogram below?

Can you place six X (crosses) in below board without making three in a row in any way ?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?