The formula to find the permutations is nPr = [tex] \frac{n!}{(n-r)!} [/tex]
Here n represents the total number of objects
r represents the number of objects taken at a time
The word TOPIC has 5 letters.
All the five letters are different.
And we need to take all 5 letters.
Hence n = 5 & r = 5
Number of arrangements = 5P5 = [tex] \frac{5!}{(5-5)!} =\frac{5!}{0!} = 5!=120 [/tex]
120 different arrangements can be made using all the letters in the word TOPIC