Question

There are 10 points on a straight line ab and 8 on another straight line ac none of them being point

a. how many triangles can be formed with these points as vertices?

Answer 1

We have 19 points in total. We need to choose 3 of them. So the formula is 19C3 = 19*18*17/(1*2*3) = 969 triangles. Please message me if the answer is something else. I shall revise my solution.

Answer 2

https://clay6.com/qa/94937/there-are-m-points-on-one-straight-line-ab-and-n-points-on-line-ac-none-of-

refer to this, there is a standard and easy way for solving this kind of problems

For this case, answer is 640