Answer:

Step-by-step explanation:
Z-score:
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 question:

You listen to the radio station for 1 hour, at a randomly selected time, and carefully observe that the amount of advertising time is equal to 17 minutes. Calculate the z-score for this amount of advertising time.
We have to find Z when X = 17. So



Answer:
The number u are looking for is 4
Step-by-step explanation:
Let X be the unknown number that we want to find.
So it becomes,
2X = 8
move 2 to the other side, so it becomes a divide
X = 8/2
X = 4
400 - 3x = 163
Add 3x to both sides.
400 = 163 + 3x
Subtract 163 to both sides.
237 = 3x
237/3 = 79
Y=x+10
y is the total cost
x is the number of toppings times $1
10 is the cost of the pizza
8 or 8 1/2 because you won't finish the ride due to 28 + 3 1/2 being odd