Answer: D
Step-by-step explanation:
Answer:
The maximum revenue is $900, obtained with 30 people
Step-by-step explanation:
Naturally, the answer should be a number equal or higher than 20, because up to 20 persons, each one pays the same. Lets define a revenue function for x greater than or equal to 20.
f(x) = x*(40-(x-20)) = -x²+60x
Note that f multiplies the number of persons by how much would they pay (here, assuming that there are more than 20).
f is quadratic with negative main coefficient and its maximum value will be reached at the vertex.
The value of the x coordinate of the vertex is -b/2a = -60/-2 = 30
for x = 30, f(x) = 30*(40-(30-20))=30*30=900
So the maximum revenue is $900.
Answer:
The value of ROE that will be exceeded by 78% of the firms is -1.77%.
Step-by-step explanation:
Problems of normally distributed samples can be 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:
The mean ROE for the firms studied was 14.93% and the standard deviation was 21.74%. This means that 
What value of ROE will be exceeded by 78% of the firms?
This is the value of X when Z has a pvalue of 1-0.78 = 0.22.
This is 
So:




The value of ROE that will be exceeded by 78% of the firms is -1.77%.
The length of an edge is the cubic root of the volume.
Cubic root 1.8 = 1.2 meters
Golden Gate Bridge, Mountains, Roller Coaster