Permutation and CombinationHard
Question
Given six line segments of length 2, 3, 4, 5, 6, 7 units, the number of triangles that can be formed by these segments is
Options
A.6C3 - 7
B.6C3 -6
C.6C3 -5
D.6C3 -4
Solution
First we select 3 length from the given 6 length so the no. of ways = 6C3
But these some pair i.e. (2, 3, 7), (2, 3, 6), (2, 3, 5) (2, 4, 6), (2, 4, 7), (2, 5, 7), (3, 4, 7) are not form a triangle so that total no. of ways is
6C3 - 7 ways
But these some pair i.e. (2, 3, 7), (2, 3, 6), (2, 3, 5) (2, 4, 6), (2, 4, 7), (2, 5, 7), (3, 4, 7) are not form a triangle so that total no. of ways is
6C3 - 7 ways
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