There are 'm' points on a straight line AB and 'n' points on the line AC none of them being the point A. Triangles are formed with these points as vertices, when

(i)A is excluded (ii) A is included. The ratio of no of triangles in the 2 cases is ?

Dear jee king

case 1   A is excluded

total ways =^m+nC3

but triangle can't be formebd joining the 3 points which are in straight line so

total number of possible triangle=^m+nC3  -^mC3  -ⁿC3

 

Case 2 A is included

otal ways =^m+n+1C3

but triangle can't be formebd joining the 3 points which are in straight line so

total number of possible triangle=^m+n+1C3  -^m+1C3  -ⁿ⁺¹C3

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