How many three-letter combinations are possible using the letters D, E, F, G, and H?
1 Answer
Jul 4, 2016
It depends on whether you may use the same letter more than once.
Explanation:
More than once:
You have a choice out of five every time:
Different letters:
For the first you can choose one out of five, then one out of four, and one out of three for the third letter:
Mind:
This difference is very important -- you should screen every question in a test for it!
