A certain type of automobile battery is known to have a lifespan that is normally distributed, with mean 1100 days and standard deviation 80 days. For how long should these batteries be guaranteed if the manufacturer wants to replace only 5% of the batteries sold because they "died" before the guarantee expired?

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The Answer of A certain type of automobile battery is known to have a lifespan that is normally distributed, with mean 1100 days and standard deviation 80 days. For how long should these batteries be guaranteed if the manufacturer wants to replace only 5% of the batteries sold because they "died" before the guarantee expired?

A Certain Type of Automobile Battery Is Known to Have