Scores on an exam appear to follow a normal distribution with = 60 and =

Question:

Scores on an exam appear to follow a normal with µ = 60 and σ = 20. The instructor wishes to give a grade of D to students scoring between the 10th and 30th percentiles on the exam.
For what range of scores should a D be given? What percentage of the students will get a D?

Distribution
The word "distribution" has several meanings in the financial world, most of them pertaining to the payment of assets from a fund, account, or individual security to an investor or beneficiary. Retirement account distributions are among the most...