In the recent years, scores on standarized test for high school students with the 3.5 to 4.0 grade point average were normally distributed, with the mean of 39.9 and standard deviation of 1.8. A student with the 3.5 to 4 grade point average who took standardized test is randomly selected.
a) Find out the probability that the students test score is less than 36
b) Find out the probability that the students test score is less than 36.6 and 43.2
c) Find out the probability that the students test score is more than 41.6