A psychology professor assigns letter grades on a test according to the following scheme.

A: Top 8% of scores

B: Scores below the top 8% and above the bottom 61%
C: Scores below the top 39% and above the bottom 16%
D: Scores below the top 84% and above the bottom 8%
F: Bottom 8% of scores

Scores on the test are normally distributed with a mean of 65.4 and a standard deviation of 9.7. Find the numerical limits for a D grade. Round your answers to the nearest whole number, if necessary.