Any help on how to attack the following problem would be appreciated.

The new recruits of a military organization who score in the bottom 16 percent on their physical conditioning tests are required to retest. If the scores are normally distributed and have an arithmetic mean of 72, what is the score at or below which the recruits are required to retest?

1.) There are 500 new recruits.

2.) 10 new recruits scored at least 82 on the physical conditioning test.