Please NEED stats help =(((?

Scholastic Aptitude Test (SAT) scores are normally distributed with a mean of 500 points and a standard deviation of 100 points. Suppose you take the SAT and several weeks later you receive a letter telling you that your results on the math portion of the test were in the 80th percentile.

Recalling that SAT scores are always expressed as multiples of 10, how many points did you get on the test?

A.600

B.85

C.690

D.580

E.550

I used a TI-83 Plus calculator and pressed 2nd Vars

(Vars is above the tangent TAN key on the calculator)

Next I went to option 2 which is the normalcdf() function

Then I did this

normalcdf(-9999, 580,500,100) = .7881

I believe that choice D is within the 80th percentile.

To find where it is exactly 80% you would do this

invNorm(.8,500,100) = 584.16

The scores are recorded in multiples of 10 so this rounds to 580.