How many 4-letter words with or without meaning, can be formed out of the letters of the word, LOGARITHMS, if repetition of letters is not allowed?
40
400
5040
2520
Explanation:
The Word LOGARITHMS contain 10 letters.
To find how many 4 letter word we can find from that = 10 $\times$ 9 $\times$ 8 $\times$ 7 = 5040.