Question

How many different selections of four letters from the 12 letters of the word REFRIGERATOR contain no Rs and two Es?

Answer 1

I would start by breaking this down.

How many unique selections of four letters are there?
How many contain no R's?
How many contain exactly 2 E's?

Answer 2

Can I do it directly using 9/2! * 4!/4!

Answer 3

Let me know how you would do it?

Answer 4

https://math.stackexchange.com/questions/2872662/permutation-selection-of-4-letters-from-12