Question

If 20 straight lines be drawn in a plane, no two of them being
parallel and no three of them concurrent, how many points of
intersection will there be?​

Answer 1

Answer:

5 points of intersection

Answer 2

Answer:

the answer is 190.

Step-by-step explanation:

Let us draw line one by one,

1st line = 0 points

2nd line = new 1 point

3rd line = new 2 points+old 1 point

4th line = new 3 points +old 2+1 points

nth line = new(n-1)points +old {(n-2)+.....+(3)+(2)+(1)} points.

So total points of intersection is S (let say)

∴S=1+2+3.....(n−1)

S=(n−1)×n/2

⇒19×20/2

⇒19×10

⇒190

S=190.

Peace ✌