Since we want just the top 20% applicants and the data is normally distributed, we can use a z-score table to check the z-score that gives this percentage.
The z-score table usually shows the percentage for the values below a certain z-score, but since the whole distribution accounts to 100%, we can do the following.
We want a z* such that:

But, to use a value that is in a z-score table, we do the following:

So, we want a z-score that give a percentage of 80% for the value below it.
Using the z-score table or a z-score calculator, we can see that:
![\begin{gathered} P(zNow that we have the z-score cutoff, we can convert it to the score cutoff by using:[tex]z=\frac{x-\mu}{\sigma}\Longrightarrow x=z\sigma+\mu](https://tex.z-dn.net/?f=%5Cbegin%7Bgathered%7D%20P%28zNow%20that%20we%20have%20the%20z-score%20cutoff%2C%20we%20can%20convert%20it%20to%20the%20score%20cutoff%20by%20using%3A%5Btex%5Dz%3D%5Cfrac%7Bx-%5Cmu%7D%7B%5Csigma%7D%5CLongrightarrow%20x%3Dz%5Csigma%2B%5Cmu)
Where z is the z-score we have, μ is the mean and σ is the standard deviation, so:

so, the cutoff score is approximately 72.
The average speed would be 53 miles per hour, hope this helped, if you need me to explain then here is the way, so all you do is divide 265 by 5 and what I did to help make it faster was split 265 into 250 and 15 so 250 divided by 5 is 50 and 15 divided by 5 is 3 so 50 + 3 = 53!
Answer:
x has to be less than 3
Step-by-step explanation: