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If there are six straight lines in a plane, no two of which are parallel and no three of which pass through the same point, then find the number of points in which these lines intersect.

Answer» Correct Answer - 15
There are six straight lines `L_(1),L_(2),L_(3),L_(4),L_(5),L_(6)` in a plane.
Since no two lines are parallel and no three of which pass through the same point, we have maximum points of intersection.
Line `L_(1)` intersect five lines, so there will be five points of intersection.
Similarly, for each of the lines `L_(2),L_(3),L_(4),L_(5),L_(6)`, there will be five points of intersection.
But there will be double counting .
So, total number of points of intersection is `(5xx6)/(2)=15`


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