Question

Se considera multimea A={1,2,3...,10}. Sa se determine numarul submultimilor cu trei elemente ale multimii A, care contin elementul 1.

Answer 1

{1,2,3};{1,2,4};{1,2,5};{1,2,6};{1,2,7};{1,2,8};{1,2,9};{1,2,10};{1,3,4};{1,3,5};{1,3,6};{1,3,7};{1,3,8};{1,3,9};{1,3,10};{1,4,5};{1,4,6};{1,4,7};{1,4,8};{1,4,9};{1,4,10};{1,5,6};{1,5,7};{1,5,8};{1,5,9};{1,5,10};{1,6,7};{1,6,8};{1,6,9};{1,6,10};{1,7,8};{1,7,9};{1,7,10};{1,8,9};{1,8,10];{1,9,10}⇒36 de submultimi cu trei elemente din multimea A care contin elementul 1.