1. A college requires applicants to have an ACT score in the top 15 % of all test scores . The ACT scores are normally distributed , with a mean of 17 and a standard deviation of 3.24 . Find the lowest test score that a student could get and still meet the college 's requirement?
2.With the conditions of problem 1, if 20 students are selected , what is the probability that the mean of their scores is greater than 18?