If `20` lines are drawn in a plane such that no two of them are parallel and so three are concurrent, in how many points will they intersect each other?

If `20` lines are drawn in a plane such that no two of them are parall

1.	If `20` lines are drawn in a plane such that no two of them are parallel and so three are concurrent, in how many points will they intersect each other?
Answer» It is given that no two lines are parallel means all line are intersecting and no three lines are concurrent means three lines intersect at a point. `therefore` Number of point of intersection `=""^(20)C_(2) = (20"!")/(2"!" 18"!") = (20 xx 19 xx 18"!")/(2 xx 1 xx 18"!")` `= (20 xx 19)/(2) = 19 xx 10 = 190`

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If `20` lines are drawn in a plane such that no two of them are parallel and so three are concurrent, in how many points will they intersect each other?

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