[Math] How many 5-letter words can we make if the letters are in order

combinationscombinatoricspermutationsstatistics

Using the $26$ English letters, the number of $5$-letter words that can be made if the letters are distinct is determined as follows:

$26P5=26\times25\times24\times23\times22=7893600$ different words.

What if the letters in each word are in alphabetical order?

For example, the word JLOQY is valid, but the word JUMPY is invalid since U can not be before M

Best Answer

Hint. How many ways can you choose the five different letters? Once you have them, in how many ways can you organize them in alphabetical order?

(This assumes the letters are distinct.)