Nick's Mathematical Puzzles
"The math puzzles presented here are selected for the deceptive simplicity of their statement, or the elegance of their solution. They range over geometry, probability, number theory, algebra, calculus, trigonometry, and logic. All require a certain ingenuity, but usually only pre-college math. Some puzzles are original.
Explaining how an answer is arrived at is more important than the answer itself. To this end, hints, answers, and fully worked solutions are provided, together with links to related mathematical topics. Further references are provided with many of the solutions. The puzzles are intended to be fun, with an educational element.
Each puzzle is assigned a level of difficulty of between one and four stars, with four being the most difficult. Clearly this is to some extent subjective, but it may be useful as a rough guide".
There are some really fun math puzzles some are very hard and some fairly simple. If you enjoy math puzzles this is one cool site.
Here is a sample one. For Math Geeks anyway. (Warning these are addictive and very time consuming).
An urn contains a number of colored balls, with equal numbers of each color. Adding 20 balls of a new color to the urn would not change the probability of drawing (without replacement) two balls of the same color.
How many balls are in the urn? (Before the extra balls are added.)
Hint.
Calculate the probabilities of drawing matching colors, before and after adding the extra balls, and equate the two. Each probability may be calculated by counting the number of ways in which matching colors can be drawn, and dividing by the number of ways in which two balls can be drawn.
For the solution see puzzle number 64.
"The math puzzles presented here are selected for the deceptive simplicity of their statement, or the elegance of their solution. They range over geometry, probability, number theory, algebra, calculus, trigonometry, and logic. All require a certain ingenuity, but usually only pre-college math. Some puzzles are original.
Explaining how an answer is arrived at is more important than the answer itself. To this end, hints, answers, and fully worked solutions are provided, together with links to related mathematical topics. Further references are provided with many of the solutions. The puzzles are intended to be fun, with an educational element.
Each puzzle is assigned a level of difficulty of between one and four stars, with four being the most difficult. Clearly this is to some extent subjective, but it may be useful as a rough guide".
There are some really fun math puzzles some are very hard and some fairly simple. If you enjoy math puzzles this is one cool site.
Here is a sample one. For Math Geeks anyway. (Warning these are addictive and very time consuming).
An urn contains a number of colored balls, with equal numbers of each color. Adding 20 balls of a new color to the urn would not change the probability of drawing (without replacement) two balls of the same color.
How many balls are in the urn? (Before the extra balls are added.)
Hint.
Calculate the probabilities of drawing matching colors, before and after adding the extra balls, and equate the two. Each probability may be calculated by counting the number of ways in which matching colors can be drawn, and dividing by the number of ways in which two balls can be drawn.
For the solution see puzzle number 64.
