Find the number of marked points on the plane, if when connected pairwise by line segments, the total number…

Find the number of marked points on the plane, if when connected pairwise by line segments, the total number of line segments formed is 15.
  1. 5
  2. 4
  3. 6
  4. 8

Solution

Let there be n points on the plane, then the number of line segments=nc2

nc2=15

⇒n(n-1)2=15

⇒n(n-1)=30

⇒n=6

Asked in: AP EAMCET 2020 (23 Sep Shift 1)

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