2019 Mock AMC 10B Problems/Problem 14

Solution 1

There are five points, and to make a triangle we need 3, so the number of ways is just This is option choice (A).

- Armpit Splash 💦 - Edits by Continuous_Pi

Note: This solution is wrong because we must consider when a subset of the points are collinear, creating degenerate triangles.

Note 2: It doesn't matter the problem is just bad and should say that no three of the points are collinear or something because if there were degenerate triangles the answer would be less than 10, but that's not an answer choice so it doesnt matter - lucaswujc