I recently came across this question which I was unable to solve.

It says:

Number of quadrilaterals that can be made using the vertices of a polygon of 10 sides as their vertices and having exactly:

a)2 sides common with the polygon

b)3 sides common with the polygon

Any help will be appreciated.

Dear student,

Make use of P and C

4 points out of 10 can be selected in 10C4 ways......

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Askiitians Expert

Sagar Singh

B.Tech, IIT Delhi

I dont think so Mr. Sagar Singh that 10C4 would be all right as it is mentioned that the quad. has (a)2 sides common and (b)3 sides common_ with the polygon!!!