Answer:
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Answer:
5.48% of the people in line waited for more than 28 minutes
Step-by-step explanation:
Normal Probability Distribution:
Problems of normal distributions can be solved using the z-score formula.
In a set with mean
and standard deviation
, the z-score of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
Mean waiting time of 20 minutes with a standard deviation of 5 minutes.
This means that 
What percentage of the people in line waited for more than 28 minutes?
The proportion is 1 subtracted by the p-value of Z when X = 28. So



has a p-value of 0.9452.
1 - 0.9452 = 0.0548.
As a percentage:
0.0548*100% = 5.48%
5.48% of the people in line waited for more than 28 minutes
(A) is the answer to the question
Answer:
x=-1
y=4
z=7
Step-by-step explanation:
3x + y - z= -6(1)
2x - y + 2z = 8(2)
4x + y - 3z = -21(3)
(1)+(2): 5x+z=2(4)
(2)+(3): 6x-z=-13(5)
(4)+(5): 11x=-11
x=-1
so z=2-5x=7
y=-6-3x+z=4