Math Problems, Probability Problems

Problem of the Day: 2/5/13

Griffin has three fiction books and two nonfiction books. If he randomly chooses three books to take on a trip, what is the probability that all three books are fiction?

Solution to yesterday’s problem:

You could solve this problem using a system of equations, but there is a much simpler way. First, consider all the factors of 108 – one of these pairs is the solution to the problem. Factors of 108 are 1,108; 2,54; 3,36; 4,27; 6,18; 9,12. We immediately notice that the sum of 9 and 12 is 21; therefore, the solution is the difference between 9 and 12, namely 3.


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