statistic
posted by shannen .
Assume that the salaries of elementary school teachers in the United States are normally distributed with a mean of $34,000 and a standard deviation of $2000. What is the cutoff salary for teachers in the bottom 10%?

Find a Percentile to ZScore Calculator. You can Google one, and likely there's a table of this in your text.
That'll tell you how many SD below the mean you have to go.
I make it about 1.28 standard deviations, so that'll be about 34,000  (1.28 * 2000) 
Assume that the salaries of elementary school teachers in the United States are normally distributed with a mean of $34,000 and a standard deviation of $2000. What is the cutoff salary for teachers in the bottom 10%?

Answer: 31,440