i forgot how to do percentages rip help me out

10% are for the idea
50% are against
and 40% have no opinion
the reason is because the total number of freshmen are 200
there are 100 who are for this idea and 100 divided by 200 is 0.5
converted to a fraction it is 50%
hope you understand this and ask me if you need more help with this type of stuff