Answer to Question #47186 in Statistics and Probability for irebami

Question

In how many ways can the word "TOPO" be arranged

12 ways
15 ways
18 ways
21 ways

Answer 1

"TOPO" is an four-letter word.
If there were no repeating letters, the answer would simply be 4!=24.
However, since there are repeating letters, we have to divide to remove the duplicates accordingly. There are 2 Os.
Therefore, there are 4!/2!=12 ways of arranging it.