How to do system of inequalities word problem

Which is greater, 7 p 5 or 7 c 5? 7p5 7c5

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.

As voters exit the polls, you ask a representative random sample of voters if they voted for a proposition. if the true percentage of voters who vote for the proposition is 63%, what is the probability that, in your sample, exactly 5 do not voted for the proposition before 2 voted for the proposition? the probability is