Note that he needs to be in the top 16% or the 84th percentile.

Thus, it can be seen in tables, that the z-score that corresponds to the 84th percentile would be .994. (If you have a TI-83, you can find this z value by inputting invNorm(.84))

Since and , we see that , which leads to something close to your result. I end up with

Does this clarify things?