statistics
posted by Sandra on .
Can you please tell me how to solve for the following?
Pedro took an exam in a class in which the mean was 64 with a standard deviation of 6. If his z score was +3, what was his exam score?
A students commute to school is normally distributed with a mean of 31 min and a standard deviation of 7 min. What is the probability that the student gets to school in 17 to 31 min?
Are the formulas the same for these?
And last one I need help with this:
Assume a normally distributed set of test scores with a mean of 100 and a standard deviation of 20. Find the probability that a person selected at random will have a score of the following:
abetween 60 and 140
bless than 60
THANK YOU! I just need to know how to solve please.

Equations are the same.
Z = (scoremean)/SD
For the second one, find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability related to the Z scores.
For the last problem, use the same equation and table.