COMEDK Exam 2022 Solved Paper

From 12 given points ‌12C2 straight lines can be drawn.
But 3 points are collinear, using 3 points ‌3C2 straight lines can be drawn.
So, total straight lines without the straight line using three points =‌12C2−‌3C2
From 3 collinear points 1 straight line can be drawn
So, total number of straight lines =12C2−3C2+1
=

12!

2!×10!

−

3!

2!×1!

+1
=

12×11×10!

2×1×10!

−

3×2!

2!×1

+1
=66−3+1=64