'An experiment testing the amount of time it takes rats to learn a particular maze finds that 5 percent of the rats never learn, and of those rats that do learn how to complete the maze, their times are approximately normally distributed with a mean of 18 minutes and a standard deviation of 4 minutes.
A) What is the probability a rat solves the maze in under 15 minutes?
B.) What is the probability a rat has not solved the maze in 20 minutes?'