I'm just looking for some guidance on where to start with this one. Anything will help me at this point. Thank you!

The average amount of precipitation in Dallas Texas during the month of April is 3.5 inches. Assume that a normal distribution applies and the standard deviation is .8 inches.

A. What percentage of the time does the amount of rainfall exceed 5 inches.
B. What percentage of the time is the amount of rainfall in April less than 3 inches?
C. A month is classified as extremely wet if the amount of rainfall is in the upper 10% for that month. How much precipitation must fall in April for it to be classified as extremely wet?