Suppose +70% of all students live in dorms. Of those who live in dorms, +40% of them eat breakfast. Of those who don't live in dorms, +30% eat breakfast.

a) Determine the percentage of students who eat breakfast
b) Calculate the percentage of students in dorms
c) Find the total percentage of students who don't eat breakfast
d) Establish the percentage of students not living in dorms who eat breakfast