Maths Puzzles

 This one is actually silly but interesting. What has four letters, sometimes has nine, but never has five?

Now that I have found subreddit for riddles, I will not have much problem finding questions to copy paste. Eh? What is the number from which if you take away half, you are left with nothing.  Hint : Not exactly mathematical 

After an unsuccessful attempt in trying to translate Upanishad (aim high, right?) and not very successful attempt in writing Sanskrit tutorial posts, I am back to riddles and puzzles. But this time, I really do not have a solution. Like many, many puzzles in life. So if you, dear reader, find a solution, please send it in the comments.  I have "borrowed" this puzzle from Quanta magazine. And there was no solution provided.  Imagine a narrow twig spanning two mounds on an anthill to form a bridge 100 inches long. There are 10 ants on the twig, evenly spaced from the left end (let’s call this coordinate 0) to close to the right end (coordinate 90). You can ignore the lengths of the ants themselves. The five ants on the left are facing right, and the five on the right are facing left.  All of the ants start walking in the direction they are facing at a constant speed of 100 inches/minute. The twig is so narrow that when two ants meet, they turn around instantaneously and

 Now this puzzle does not have a reasonable solution. Because the question itself is quite illogical. But that is how you have to expand your brain, right? If you can place a fireman's pole from moon's surface to earth, how long will it take for you to climb down from moon to earth? Ramon, Germany The question was asked by his 5 year old son. Well, children have immense capacity to wonder. And germans are the smartest people on earth. Next only to us Indians of course. And if you are looking for a very detailed very scientific solution, look at whatif section of xkcd.com

 This one is a silly puzzle. But it only interests us because it has a cute picture. Can you solve it?