At Least Two Digits Equal
Difficulty: Easy · Topics: Discrete Mathematics, Combinatorics, Counting Principle
A=\1,2,3,4\
Using elements of A (digits may repeat), how many three-digit numbers have at least two equal digits?
Difficulty: Easy · Topics: Discrete Mathematics, Combinatorics, Counting Principle
A=\1,2,3,4\
Using elements of A (digits may repeat), how many three-digit numbers have at least two equal digits?