When it's bad luck to meet a black cat?

John and Jacob are playing bets. John gives $10 to Jacob and Jacob deals four cards out of a normal 52-card deck which are chosen by him completely randomly. Jacob keeps them facing down takes the first card and shows it to John. John has a choice of either keeping it or looking at the second card. When the second card is shown to him, he again has the choice of keeping or looking at the third which is followed by the third card as well; only if he does not want the third card, he will have to keep the fourth card.

If the card that John is choosing is n, Jacob will give it to him. Then the cards will be shuffled and the game will be played repeatedly. Now you might think that it all depends on chance, but John has come up with a strategy that will help him turn the favor in his odds.

Can you deduce the strategy of John?

You were playing ping pong with your friend. Suddenly the ball fell into a narrow metal pipe that was imbedded in the concrete surface of the floor one foot deep. Now you don't have any other ball and you desperately want to take it out and play. You and your friend have your shoelaces, your tennis paddle and a plastic water bottle. However, the bottle cannot fit into the pipe.

How will you take the ball out?

What is the fastest way to double your money?

If 1+9+8=1, what is 2+8+9?

What do you think with the below Picture ?

Andrew’s doctor gives him three pills and tells him to take one every half hour. How much time will have passed by the time Andrew’s taken all three pills?

What has to be broken before you can use it?

The doctor advised his patient to take a tablet after every fifteen minutes. He gave him five tablets in total.

How much time will he take to have all the five tablets?

How many triangles can you count in the figure given?