Can anyone help me what Formulas we use for those questions. I only need formula not calculation. Thank you!

1, Say you decide to create League of Legends knock-off game where you have 40 possible characters to choose from. You have the same 5 roles as in League of Legends: Top, Bottom, Mid, Jungle, and Support. If there are 4 characters who would be good as Jungle, 7 characters who would be good as Support, but only 2 of those characters who would be good as Jungle and Support, how many characters would not be good as either jungle or support? Please show the formulas you would use for this.