What does an Island and the letter T have in common?

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

What are the next two letters in the following series and why?
W A T N T L I T F S _ _

*Hint: Check Puzzle Title

Below the four parts have been reorganised. The four partitions are exactly the same in both arrangements. Why is there a hole?

Can you solve this picture maths equation?

John gave half of the apples he had plus one more to Jacob. He gave half of the remaining ones plus one more to James. Now, John was left with just one apple.

Can you find out how many did he have in the beginning?

John said, "If yesterday was tomorrow, today would be Friday."

When did John make this statement?

What is full of holes but still holds water?

You find yourself in a strange place guarded by two guards.One of the guard always say truth while other always lies.You don't know the identity of the two.You can ask only one question to go out from there. What should you ask?

You are presented with three boxes. One of them has a red ball inside and the other two have a black ball inside each of them. You are asked to pick up the one with red ball and you pick one. Now, one of the other boxes is opened and it is found to have a black ball.

You are presented with a chance to change your box with the one that is left closed. Will you change your box? Why or why not?