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Math PuzzlesNote: Some puzzles require algebra or more advanced math. #1 -Amoebas reproduce by splitting in two. An amoeba which does so every minute is placed in a jar at exactly ten o'clock in the morning. At 12:00 noon the jar is full. At what time is the jar half full? Check your answer #2 -Where does the extra square centimeter go? 
#3 -Three travellers register at a hotel and are told that rooms will cost \$30. They decide to share a room and pay $10 each. Later the clerk realizes that he made a mistake and should only have charged them $25. He gives a bellboy $5 to return to them but the bellboy is dishonest and gives them each only $1, keeping $2 for himself. So the men spent $27 together and the bellboy kept $2 - what happened to the other dollar of the original $30? #4 -A three volume set of books stands on the bookshelf. Each cover is 1/4 of an inch thick and the pages of each book are 1 inch thick. A bookworm starts on page 1 of volume 1 and eats his way to the last page of volume 3. How far does he travel? Check you answer #5 -The length of a certain fish is equal to 20 plus 1/2 its length. The head of the fish is 9 inches; the body is equal to the head plus the tail. How long is the body? The tail? Check your answer #6 -The Smiths have a certian number of birdhouses in their yard and all are occupied. Since there are more birdhouses than there are birds living in any one house, at least two of the birdhouses must contain the same number of birds. True? #7 -A group of airplanes is based on a small island. The tank of each plane holds just enough fuel to take it half way around the world. Fuel can be transferred from the tank of one plane to the tank of another while in flight. The only source of fuel is on the island and we will assume there is no time lost in refueling either in the air or on the ground. What is the smallest number of planes that will ensure the flight of one plane all the way around the world (on a great circle) assuming that all planes have the same constant ground speed and rate of fuel consumption and that all planes return safely to the island? Check your answer #8 -Fill in the squares in the following diagram with numbers from 1 to 8 so that no number is adjacent to one that is in sequence with it either horizontally, vertically or diagonally. 
#9 -A frog in a well 20 feet deep jumps up 5 feet each day but falls back 4 feet. How many days until he gets out? Check your answer #10 How many nines are there counting from 1 to 100? Check your answer #11 -8 men wanted separate rooms in a hotel but there were only 7 rooms available. The clerk said he could handle it and proceeded to put 2 men in the 1st room, the third man in the 2nd room, the fourth man in the 3rd room, the fifth man in the 4th room, the sixth man in the 5th room, and the seventh man in the 6th room. He now took one of the men out of the 1st room and placed him in the last, the 7th, room. So he managed to put 8 men in 7 rooms with each one having a separate room. Did he really? #12 -A man travels on a train from London to Glasgow at 100mph. On his return journey, the train only travels at 60mph. What is his average journey speed ? Check your answer #13 -There were about 40-50 students in the lecture. The lecturer said that he would bet anyone in the room that at least two people definitely have their birthday on the same day.
Assuming nobody knows the birthday of anyone else (except themselves obviously), how many
people need to be in the room to have a better than even chance that at least two people have their birthday on the same
day ?
#17 -If six cats can kill six rats in six minutes, how many cats does it take to kill a hundred rats in fifty minutes? #18 -In a twenty-four hour time period, how many times are the hour hand and the minute hand on a clock at a right, or 90 degree, angle? |