The life span of a battery is the amount of time the battery will last. The distribution of life span for a certain type of battery is approximately normal with mean 2.5 hours and standard deviation 0.25 hour. Suppose one battery will be selected at random. Which of the following is closest to the probability that the selected battery will have a life span of at most 2.1 hours?

The probability that the selected battery will have a life span of at most 2.1 hours is 0.0548.

Given information:

The life span of a battery is the amount of time the battery will last.

The distribution of life span for a certain type of battery is approximately normal with a mean of 2.5 hours and a standard deviation of 0.25 hours.

The z-value for the probability that the selected battery will have a life span of at most 2.1 hours will be calculated as,

Now, use the standard normal distribution table or curve to get the value of required probability as,

Therefore, the probability that the selected battery will have a life span of at most 2.1 hours is 0.0548.

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0.0548

Step-by-step explanation:

The distribution of life span for a certain type of battery is approximately normal with mean 2.5 hours and standard deviation 0.25 hour.

To find the the probability that a selected battery will have a life span of at most 2.1 hours, we need to first determine the z-score for x=2.1 hours using

We substitute the values to get:

We read read -1.6 from the standard normal distribution table to get:

P(X≤2.1)=0.0548

54 kilometers per hour

step-by-step explanation:

according to rules:

1 km = 1000 meter

which means that 1 meter = 1/1000 km

1 hour = 3600 second [ as 1 hour = 60 min = 60 *60 seconds ]

which means that 1 second = 1/3600 hour

therefore, 1 kilometer/hour =

thus to convert 15 meter per second to kilometer per hour, we multiply 15 to 3.6 kilometer/hour.

15 meter/second=   which is the required answer.