Question

How many ways are there to get two questions wrong out of 8 questions? I looked it up and it says 28 ways but how do you get the answer?

Answer 1

You can get 1-2 2-3 3-4 4-5 5-6 6-7 7-8
1-3 1-4 1-5 1-6 1-7 1-7 1-8
2-4 2-5 2-6 2-7 2-8
3-5 3-6 3-7 3-8
4-6 4-7 4-8