Maths Puzzles

 Three statements are made about the books owned by David. Thomas - David owns more than thousand books.    Richard : No, he owns fewer than that.   Harry : He certainly owns at least one book.  Only one of these three statements are true. Who is right?    Find the solution here .  

There is a place called the Island of Knights and Knaves, where knights always tell the truth and knaves always lie and every inhabitant is either a knight or a knave. On this particular island, each woman is either a constant liar or a constant truth teller. The men are as usual—knights and knaves. In this island, I was introduced to three married couples—the Arks, the Bogs, and the Cogs. One of the three couples is the king and queen of the island. I was reliably informed that in none of the couples are both of them liars. They all made the following statements:  Mr. Ark: I am not the king.   Mrs. Ark: The king was born in Italy.    Mr. Bog: Mr. Ark is not the king. Mrs. Bog: The king was really born in Spain.    Mr. Cog: I am not the king. Mrs. Cog:  Mr. Bog is the king. Who is really the king? You can find the solution here.

The puzzle was  There is a closet and a light bulb inside this closet. You can not see whether the bulb is on or off from outside. There are three switches outside the closet one of which controls the light bulb. You can not see these switches from the closet. How do you find out which switch controls the bulb with a single try? Now let us look at the solution. Switch on the first switch wait for 2-3 minutes and then switch it off. Switch on the second switch. Now go inside the closet. If the bulb is on, then second switch is the switch for the bulb. If bulb is off, touch it. If it is warm then first switch is the switch. If not third switch is the switch for the bulb