how many triangles can be formed if there are 10 points in a plane out of which 4 are in a line.

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25 Mar 2011 triangle

how many triangles can be formed if there are 10 points in a plane out of which 4 are in a line.

OPtion

1) 116
2) 120
3) 124
4) 130
5) 140
6) 156
7) 165
8) 190
9) 200
10) 240

Solution

3 points are required to form a triangle so no. of triangles formed = 10*9*8/3*2*1 = 120
but out of these points 4 are in a line so rejected methods are 4*3*2/3*2*1 = 4
answer = 120-4 = 116

Correct Option: 1 Best Solution (0)