2003 AMC 12A Problem 8

Attempt Problem 8 of the 2003 AMC 12A below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2003 AMC 12A solutions, or check the answer key.

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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}

Answer: E
Concepts:factor countingbasic probability
Difficulty rating: 1270
Solution:

The number 6060 has 1212 positive factors: 1,2,3,4,5,6,1,2,3,4,5,6, 10,12,15,20,30,60.10,12,15,20,30,60.

Six of them are less than 7,7, namely 1,2,3,4,5,6,1,2,3,4,5,6, so the probability is 612=12.\dfrac{6}{12}=\dfrac12.

Thus, the correct answer is E.

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