#### 7) If you take two points at a time, howmany lines can you draw with:(i) 3 collinear points(ii) 3 non-collinear points?

$(i)\;Only\;one\;line\;can\;be\;drawn\;through\;three\;collinear\;points. \\* (ii)\;We\;need\;two\;points\;to\;draw\;a\;line.\\*Number\;of\;lines\;drawn\; through\;non\;collinear\;points\\*\Rightarrow _{}^{3}\textrm{C}_2=\frac{3!}{(3-2)!\;2!}=\frac{3\times 2!}{2!}=3$