When Ryan runs the 400 meter dash, his finishing times are normally distributed with a mean of 75 seconds and a standard deviation of 0.5 seconds. Using the empirical rule, determine the interval of times
that represents the middle 68% of his finishing times in the 400 meter race.

10 points help !!

Of 400 people at the school carnival, 95% are students and the rest are teachers. a. how many students are at the school carnival? b. if 55% of the students at the school carnival are boys, how many are girls? c. how many teachers are at the school carnival? d. if 35% of the teachers are male and the rest are female, how many female teachers are at the carnival?