how many lines are determined by 10 points. no 3 of which are co-linear.

Question

anonymous · Answer

is answer 45. I just want to cross check. In book answer is 150.

anonymous · Answer

Is this the exact question? are there any more conditions?

anonymous · Answer

no more conditions.

anonymous · Answer

well immediately one would think that the answer is $\left(\begin{matrix}10 \ 2\end{matrix}\right)=45$ but that doesn't seem to be the case hmmmm.

anonymous · Answer

are u sure the book is right?

anonymous · Answer

Pretty sure 45 is right. Just did a google search and found this: http://ca.answers.yahoo.com/question/index?qid=20110216112046AAYA0O9 also other sources give the same answer so the book is probably wrong or you're looking at the wrong answer.

anonymous · Answer

book is wrong. We are correct.

anonymous · Answer

I too got the same answer.