Question

Ten points are chosen in a plane, no three of which are collinear.

I don't really understand the wording of this problem can someone explain?

Answer 1

No three points are on a single straight line ?

http://mathworld.wolfram.com/Collinear.html

Answer 2

well the questions asks

How many lines can be drawn thought the pairs of the points

Answer 3

it means that two points are collinear right?

Answer 4

Two points are trivially collinear since two points determine a line.

Answer 5

i have the answer but I'm not sure why?

Answer 6

its supposed to be 10!/2!8!

Answer 7

can you explain it to me ?

Answer 8

Because, for any point you pick (and there are 10 of them), you can draw a line through any of the other 9 points.

But you need to divide by 2, since you counted each line twice.

Answer 9

So it's 10*9/2

Answer 10

oh wait its 10 C 2 right?

Answer 11

If 10C2 = 10*9/2

:)

Answer 12

oh yeah lol thanks heaps:)

Answer 13

yw