0

Letters $A$ to $J$ is a random number.

If only $A$ is used. There is just $A$. Which is $1$ scenario If $A$ and $B$ are used. There are $2$ scenarios. $(A=B) (A<>B)$

If$ A, B$ and $C$ are used. There are $5$ scenarios. $(A=B,A<>C)(A=C,A<>B)(B=C,B<>A)(A<>B<>C)(A=B=C)$

If all $10$ letters are used. How many possible scenarios are there?

Andrews
  • 3,953
Elton Lim
  • 1

1 Answers1

1

It appears that you are looking for Bell numbers, the number of equivalence relations on a finite set. $B_{10}=115975$

saulspatz
  • 53,131