In a class, the final grade is determined by a single test. The scores in the test are normally distributed with a mean of 75 and a standard deviation of 10. The students receiving the top 10% of the scores will receive an A; the next 20%, a B; the next 40%, a C; the next 20%, a D; and the remaining 10%, an F.

What is the minimum score for a B grade?(Answer to 1 decimal place).