Answer:
A score of 150.25 is necessary to reach the 75th percentile.
Step-by-step explanation:
Problems of normal distributions 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.
A set of test scores is normally distributed with a mean of 130 and a standard deviation of 30.
This means that 
What score is necessary to reach the 75th percentile?
This is X when Z has a pvalue of 0.75, so X when Z = 0.675.




A score of 150.25 is necessary to reach the 75th percentile.
$200 divided by 100 customers = 2$.
So, if he wants to make a profit of $200, he would have to make each customer pay $2. :)
Answer:
10
Step-by-step explanation:
(-1 - 3i)(-1 + 3i) = 1 - 3i + 3i -9i²
1 - 9i²; i² = -1, therefore 1 - 9(-1) = 1 + 9 = 10
Answer: 138x + 27
Step-by-step explanation:
First you distribute the 3, creating 102x +27.
Then you combine like terms, creating 138x + 27
You can't do anything else so that's your answer.