Question

There are $11$ points in a plane out of which $4$ are collinear. How many straight lines can be obtained with these points?

• A. $40$
• B. $50$
• C. $49$
• D. $45$

Answer 1

The correct option is B $50$

$11$ points are in plane , out of which $4$ are collinear.

1. Choose $2$ points from $7$ non collinear points.

2. Choose any $1$ point from set of collinear points and $1$ from the set of non -collinear points.

3 . There would be $1$ line passing through $4$ collinear points

${=}^4{C}_1{\times }^7{C}_1{+}^7{C}_2+1=50$