Answer:
Standard deviation = 11.30 m/h
Mean = 57.74 m/h
Step-by-step explanation:
Assume that the travel speed is normally distributed.
The corresponding z-score to the 5th and 90th percentile of normal distribution are, respectively, -1.645 and 1.282.
For any given speed X, the z-score is:

If z = -1.645 for X = 39.15 and z= 1.282 for X=72.23, the following system can be solved for the mean and standard deviation of vehicle speed:

The standard deviation is 11.30 m/h and the mean is 57.74 m/h.
Answer:
-4
Step-by-step explanation:
Consider (-4, -2) and (-2, -10).
Change in x: 2
Change in y: -8
Slope = (change in y)/(change in x) = -4
A=8 because you divide 56 by 7
Answer:
D is your answer.
Step-by-step explanation:
Surface area is equal to all faces on the prism.
If you simplify it:
(5)(12) + (5)(10) + (12)(10) + (13)(10)
SA = 360 cm^2
Feel free to let me know if you need more help. :)
Also, you're not dumb. Everyone needs help at some point. :)