It’s D
This is the right answer
Answer:
0.9898 = 98.98% probability that there will not be more than one failure during a particular week.
Step-by-step explanation:
In a Poisson distribution, the probability that X represents the number of successes of a random variable is given by the following formula:

In which
x is the number of sucesses
e = 2.71828 is the Euler number
is the mean in the given interval.
3 failures every twenty weeks
This means that for 1 week, 
Calculate the probability that there will not be more than one failure during a particular week.
Probability of at most one failure, so:

Then



Then

0.9898 = 98.98% probability that there will not be more than one failure during a particular week.
If you mean by x over 4 that it is fraction then there is no different between it and divisions
x/4 = -120
x = -120 × 4 ( when division goes to the other side of equal it turns into multiplication)
x = -480
A. -480
Ok sure! Let's start with the marbles first. We have one red one blue and one green. There is a red and a blue cube. All we do is list the possible combinations of one marble and one cube. The answer would be : 1 blue marble, 1 blue cube. 1 red marble, 1 blue cube. 1 green marble, 1 blue cube. Then again but with the red cube. So in all, there are 6 possible combinations. Hope this helps. ☺️