At Least Two Letters
Difficulty: Medium · Topics: Discrete Mathematics, Sets, Subsets
A=\1,2,3,4,a,b,c\
In how many of the four-element subsets of A are there at least two letters?
Difficulty: Medium · Topics: Discrete Mathematics, Sets, Subsets
A=\1,2,3,4,a,b,c\
In how many of the four-element subsets of A are there at least two letters?