There is a box in which distinct numbered balls have been kept. You have to pick two balls randomly from the lot.

If someone is offering you a 2 to 1 odds that the numbers will be relatively prime, for example
If the balls you picked had the numbers 6 and 13, you lose $1.
If the balls you picked had the numbers 5 and 25, you win $2.

Will you accept that bet?

I have an eye but still cannot see.

Who am I?

Can you write down eight eights so that they add up to one thousand?

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

Count the squares in the matchstick puzzle below?

Different lights make me strange by changing me into different sizes. What am I?

Assume the given figure to be a delicious doughnut. Yes, now you can concentrate more on the puzzle. So you have this delicious doughnut in your refrigerator when your friends come knocking at the door. There are eight of them. Now you have to make three cuts in this doughnut so that each one of you nine people can enjoy a piece of it. Neither you nor your friends would mind the size of their piece as long as they are getting it. How will you do it?

There is a shop where written:
Buy 1 for $1
10 for $2
100 for $3
I needed 999 and still only paid $3. How could this be financially viable for the shop-keeper?

Prove that the below maths equation is true.

8 + 8 = 91

Using Only Five 5's and any mathematical operator make sum as 37