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The life expectancy of a particular brand of tire is normally distributed with a mean of 40,000 and a standard deviation of 5,000 miles. what is the probability that a randomly selected tire will have a life of at least 30,000 miles?

User Catasaurus
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The z-score of 30,000 is -2. Reference to a normal standard distribution table shows that 97.72% of tires will have a life of at least 30,000 miles.
User Suzu
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