please answer and show work

A stats class was interested in determining the percentage of students on their campus who are opposed to a new policy eliminating all paper books from the campus bookstore in favor of ebooks. After surveying 186 students, the class finds that 31% are opposed to the policy. The margin of error is 6.8%. If surveying more students keeps the percentage at 31%, how many more would need to be surveyed in order to be 95% confident that the correct percentage for the entire student body is between 28% and 34%? Don't forget to consider the number of students that have already been surveyed. Round up to the nearest student, if necessary. (Hint: What would the margin of error be in this case?) In order to be 95% confident that the correct percentage for the entire student body is between 28% and 34%, the class needs to survey more students