Algebra 2 Problem, Combinations/Permutations
I'm having trouble figuring out how to start this problem, and why my answer is always incorrect. I keep getting 435, but I am marked wrong. Please help! Here's the problem:
In an economics class with 30 students, the teacher wants 2 different students to answer problems 4 and 9 in front of the class. In how many ways can the teacher pick students for the problems?