Students in a college are discussing two proposals --
A: a proposal by the authorities to introduce dress code on campus, and
B: a proposal by the students to allow multinational food franchises to set up outlets on college campus.

A student does not necessarily support either of the two proposals.

In an upcoming election for student union president, there are two candidates in fray: Sunita and Ragini. Every student prefers one of the two candidates.

A survey was conducted among the students by picking a sample of 500 students. The following information was noted from this survey.

1. 250 students supported proposal A and 250 students supported proposal B.
2. Among the 200 students who preferred Sunita as student union president, 80% supported proposal A.
3. Among those who preferred Ragini, 30% supported proposal A.
4. 20% of those who supported proposal B preferred Sunita.
5. 40% of those who did not support proposal B preferred Ragini.
6. Every student who preferred Sunita and supported proposal B also supported proposal A.
7. Among those who preferred Ragini, 20% did not support any of the proposals.

Question 1: Among the students surveyed who supported proposal A, what percentage preferred Sunita for student union president?

Question 2: What percentage of the students surveyed who did not support proposal A preferred Ragini as student union president?

Question 3: What percentage of the students surveyed who supported both proposals A and B preferred Sunita as student union president?

Question 4: How many of the students surveyed supported proposal B, did not support proposal A and preferred Ragini as student union president?

I tried this with set theory but everytime I messed up.

Please help me.