Finding percentage from standard deviation and mean?

Question

The scores on the Wechsler Adult Intelligence Scale are approximately Normal with mean 100 and standard deviation 15. The score needed to be among the highest 10% of all scores is closest to? Steps to solve it would be awesome :)

Answer 1

Excel offers the ability to determine this without first calculating the z value.

The highest 10% means the 90th percentile.

=NORM.INV(0.9,100,15) = 119.2233