Question

out of 25 points in a plane, no three are in a straight line except 8, which are collinear.
how many straight lines can be formed​

Answer 1

Answer:

18 points,5 collinear :

(a) No. of lines =

18

C

2

-

5

C

2

+ 1 = 153 - 10 + 1 = 144

(b) No. of Δ

s

=

18

C

3

-

5

C

3

= 816 - 10 = 806.