Question: 1. Use a truth table to show that ((¬p)∧q)∧(p∨(¬q)) is a contradiction.
2. Prove that the graph shown in Figure is nonplanar.
![83_14.jpg](https://secure.tutorsglobe.com/CMSImages/83_14.jpg)
3. An upper-level math class has 12 students: 3 of them live off campus and 9 live on campus. How many ways can a project group of three students be chosen so that it has two on-campus members and one off-campus member? Explain briefly.