A humanities professor assigns letter grades on a test according to the following scheme. A: Top 12% of scores

B: Scores below the top 12% and above the bottom 60%
C: Scores below the top 40% and above the bottom 17%
D: Scores below the top 83% and above the bottom 7%
F: Bottom 7% of scores

Scores on the test are normally distributed with a mean of 77 and a standard deviation of 10. Find the numerical limits for a B grade. Round your answers to the nearest whole number, if necessary.