A study shows that scores on an aptitude test are normally distributed

A study shows that scores on an aptitude test are normally distributed with a mean of 70 and a standard deviation of 12. Find the following probabilities: (6 Points each) a. If one test taker is selected, that the person scored greater than 75. b. If 9 test takers are selected, that they have a mean score greater than 75. c. If 49 test takers are selected, that they have a mean score greater than 75.