2003 AMC 10A Problem 8

Below is the professionally curated solution for Problem 8 of the 2003 AMC 10A, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2003 AMC 10A solutions, or check the answer key.

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Concepts:factorbasic probability

Difficulty rating: 1250

8.

What is the probability that a randomly drawn positive factor of 6060 is less than 7?7?

110\dfrac{1}{10}

16\dfrac{1}{6}

14\dfrac{1}{4}

13\dfrac{1}{3}

12\dfrac{1}{2}

Solution:

The factors of 6060 are 1,2,3,4,5,6,10,12,15,20,30,1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, and 60.60.

Six of these twelve factors are less than 7,7, so the probability is 612=12.\dfrac{6}{12} = \dfrac{1}{2}.

Thus, the correct answer is E.

Problem 8 in Other Years