Pls explain step by step cause im kind of confused on how to do it. If you can explain it to me on paper, it will be great. Thank u so much!!!!!!

Suppose that a student suffering from migraine has a medical history that indicates the following probabilities. The probability that you will have a migraine in one day is 25%. If she has a migraine one day, the probability that she will have a migraine the next day is 40%. If she does not have a migraine, the probability that she will have a migraine the next day is 20%. What is the probability that she has a migraine:

a) in only one of two days?

b) at least one of two days?