A bookstore has determined that weekly sales of a pop culture magazine can be

modeled by an approximately Normal distribution with a mean of 75 copies and a

standard deviation of 6 copies.

a) For what percentage of the weeks can the store expect to sell between 70 and 85

copies of the magazine?

b) For what percentage of the weeks can the store expect to sell less than 66

magazines?

c) If the bookstore stocks 86 copies of the magazine, for what percentage of weeks

will there be an insufficient number of copies to meet demand?

3. A manufacturing company has designed a new test of mechanical aptitude for its

machinists. Scores on this test approximate a Normal distribution with =400 and =

60. What score would a machinist need in order to be in the top 10% of all machinists

who would take this test?