Working this kind of problem will require tables or some other form of "lookup".
Here is the perfect method to replace good ol' tables in back of textbooks
http://davidmlane.com/hyperstat/z_table.html
click on "value from area"
enter .12 in "area"
enter 37000 in "mean"
enter 3500 in SD
click on "below" and
lo and behold ----- cutoff salary is $32887
Assume that the salaries of elementary school teachers in the U.S. are normally distributed with a mean of $37,000 and standard deviation of $3500. The cutoff salary for teachers in the bottom 12% is
1 answer