Answer:
36.58% probability that one of the devices fail
Step-by-step explanation:
For each device, there are only two possible outcomes. Either it fails, or it does not fail. The probability of a device failling is independent of other devices. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

In which
is the number of different combinations of x objects from a set of n elements, given by the following formula.

And p is the probability of X happening.
A total of 15 devices will be used.
This means that 
Assume that each device has a probability of 0.05 of failure during the course of the monitoring period.
This means that 
What is the probability that one of the devices fail?
This is 


36.58% probability that one of the devices fail
Step-by-step explanation: To find the volume of a sphere, start with the formula for the volume of a sphere which is shown below.

Here, we are given that our sphere has a radius of 4 units.
So plugging into the formula, we have
.
Start by simplifying the exponent.
(4 units)³ is equal to (4 units) (4 units) (4 units) or 64 units³.
So we have
.
Next, we multiply (4/3)(64) which can
be thought of as (4/3)(64/1)
So multiplying across the numerators and across the denominators,
we have
.
First we are going to find the common denominator of both fractions. To do that, we are going to multiply their denominators:

Now we can rewrite our expression using the common denominator:

Finally, we can use the trig identities:

and

to simplify our trig expression:
We can conclude that the correct answer is the fourth one.
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