Who always enjoys poor health?

If we add four times the age of John four years from now to five times his age five years from now we get ten times his current age.

How old will John be two years from now?

Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

Count the Triangle in the figure given below:

A father's child, a mother's child, yet no one's son.

Who am I?

You have two buckets of 11 liters and 6 litres.
How can you measure exactly 8 litres?

How can you take 2 from 5 and leave 4?

How high do you have to count before you use the letter “a” in the English spelling of the whole number?

What word is pronounced the same if you take away four of its five letters?

In the Wild West, you are challenged into a death match by two bounty hunters nicknamed Golden Revolver (GR) and Killer Boots (KB). You accept the challenge. None of you want to waste any of the bullet and so a certain rules are laid down:

1) All of you will shoot in a given order till the last man standing.
2) Each of you shoots only once upon his turn.
3) If any one of you is injured, the other two will finish him off with an iron rod.
4) The worst shooter of all (which is you) shoots first and the best one shoots at the last.

Now, how will you plan things if you know that you hit every third shot of yours, KB hits every second shot and GR hits every shot ?