There 300 graduating students in class. 165 take the math subjects and 185 students take
the English,105 students take both English or Math. What is the probability if
A.Both students take English or Math?
B.Remaining student doesn't take both subjects.
C.Students take only the English not Math

Draw a venn diagram, this will definitely help you in this kind of question.

Also, you have to know that the probability of an event is given by the required outcomes over the possible outcomes.

A. Find the number of students who study only Math, only English and you are given those that do both. The answer to the question A is the total of the students I just mentioned here over the total number of students, multiplied by the total of the students I mentioned above minus one, that over the total number of students minus one.

B. Take the total number of students studying Math only, English only and both of them, and subtract that from the total number of students. Put that value over the total number of students to get the answer for B.

C. From your venn diagram, you already have the number of students taking English only. Do the math.