Home > Practice > Arithmetic Aptitude > Permutations and Combinations > Miscellaneous
1. There are 10 points in a plane out of which 4 are collinear. Find the number of triangles formed by the points as vertices.
Similarly, the number of triangle can be formed by 4 points when no one is collinear = 4C3
In the question, given 4 points are collinear,Thus, required number of triangle can be formed,
= 10C3 - 4C3
= 120 - 4
= 116
Solution:
The number of triangle can be formed by 10 points = 10C3Similarly, the number of triangle can be formed by 4 points when no one is collinear = 4C3
In the question, given 4 points are collinear,Thus, required number of triangle can be formed,
= 10C3 - 4C3
= 120 - 4
= 116