The amount of time to complete a physical activity in a PE class is normally distributed with a mean of 35.3 seconds and a standard deviation of 5 seconds. Round answers to 4 decimal places.

a) What is the probability that a randomly chosen student completes the activity in less than 32.9 seconds?

b) What is the probability that a randomly chosen student completes the activity in more than 38.1 seconds?

c) What proportion of students take between 31.2 and 39 seconds to complete the activity?

d) 70% of all students finish the activity in less than seconds.