probability that both modems selected are substandard

Mary Jane

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Nov 2, 2006
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5
A manufacturer stores computer modems in batches of 500. In one particular batch, 150 of the modems were substandard. An inspector selects 2 modems at random. What is the probability that both are substandard?
 
\(\displaystyle \L \frac{150 \choose 2} {500 \choose 2}\)
 
Another way:

\(\displaystyle \L\\\left(\frac{150}{500}\right)\left(\frac{149}{499}\right)\)
 
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