Answer:
A.
B.
C.
D.
Step-by-step explanation:
A. To solve the first part of the problem we must replace in the function
So:
B. In part B we must find the inverse function of
To find the inverse function do
Now clear the variable x.
Replace x with y.
Finally
C. Now we take the inverse function found above and replace
D. Now we substitute in the original function.
Answer:
171 newspapers.
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean and standard deviation
, the zscore 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 pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:
How many newspapers should the newsstand operator order to ensure that he runs short on no more than 20% of days
The number of newspapers must be on the 100-20 = 80th percentile. So this value if X when Z has a pvalue of 0.8. So X when Z = 0.84.
So 171 newspapers.