The mean time it takes a group of senior high students to compete a certain examination is 50.6 minutes. The standard deviation is 6 minutes. Assume that the variable normally distributed. What is the...

The mean time it takes a group of senior high students to compete a certain examination is 50.6 minutes. The standard deviation is 6 minutes. Assume that the variable normally distributed. What is the probability that a randomly selected senior high school student will complete the examination in less than 48 minutes?