Question

there are 25 points on a plane of which 7 are collinear.how many triangles can be formed

Answer 1

6 is the right answer

Answer 2

Answer:

The number of triangles form is : 2265

Step-by-step explanation:

Hey Mate,

Triangle has 3 side , So its take 3 Points.

The total number of ways it can be done among 25 points

=> ²⁵C₃

But,

Seven points are collinear and So that won't contribute to a triangle.

If all of the 3 Points are chosen from these 7 vertices as they form a line not a triangle.

So we need to subtract that.

So the number of triangles form is :

=> ²⁵C₃ - ⁷C₃

=> 2265