Answer:
The mathematical expectation of a student who purchases 10 tickets is -$39.65.
Step-by-step explanation:
A student that purchases 10 tickets out of 2900 has a probability of winning the cruise that can be calculated as:

Each ticket cost $5, so he has spent $50 for the 10 tickets.
Then, the expected value of this operation is equal to the expected value of the earnings (probability of winning the prize multiplied by the value of the prize), minus the costs:

The mathematical expectation of a student who purchases 10 tickets is -$39.65.
The difference in gallons per day used is 3.6.
The formula to calculate a z-score is:

,
where X is the value used to calculate the score, μ is the mean and σ is the standard deviation. We have the z-scores so we must work backward:

For both equations, we will cancel the 1.2 by multiplying both sides:

Now we will cancel 2.2 from both equations by adding it to both sides:
3.6+2.2=X-2.2+2.2 and 0+2.2=X-2.2+2.2
5.8=X and 2.2=X
The difference in gas used per day would be given by
5.8-2.2 = 3.6.
Well, the y-intercept is represented by B. So b would be the dot crossing the y-axis in each graph (which you already circled). Next, the slope for top left is: -1.5, top right is: -1.7, bottom left is: 3, and bottom right is: 1.33. I got those by using this very helpful website named Desmos. Now, I’m order to write the equation for each graph is very simple, all you have to do is put in the slope and y-intercept into the equation. For example, the top left one would be:
y = -1.5x + 4 since we know that the slope is equal to -1.5 and the y-intercept is equal to 4. Hope this helps :)
Answer:
6.75
Step-by-step explanation: