Chapter 11.5, Problem 69E

Grading on a curve. An instructor grades on a curve by assuming that grades on a test are normally distributed. If the average grade is $70$ and the standard deviation is $8$, find the test scores for each grade interval if the instructor assigns grades as follows: $10\%\text{ A’s}$, $20\%\text{ B’s}$, $40\%\text{ C’s},20\%\text{ D’s}$, and $10\%\text{ F’s}$.