can you please help me with this? I will mark it helpful,thanks in advance.Hope you have a good day?

1. The mean surf time of students in the computers is 18 minutes with a standard deviation of 4 minutes. What is the probability that a student surfs for 15 to 20 minutes? 2. The scores on a Pre calculus Test follow a normal distribution with a mean of 50 and standard deviation of 3. Find the probability that the score is above 54. 3. Zean scored 46 on a Biology long Test. Her Biology class' scores follow a normal distribution with a mean of 48 and standard deviation of 4. She also scored 48 in a Math test from a class with normal distribution with a mean of 50 and standard deviation of 5. In which test did she performed better