Sixty points lie on a plane, out of which no three points are collinear. How many straight lines can be formed by joining pairs of points ?

Explanation

Sixty points lie on a plane, out of which no.3 points are collinear. A straight line required two points.
The number of straight lines formed by joining 60 points is `""^60C^2 = (60!)/(2xx58!)=(60xx59)/2=1770`