How many different arrangements of the letters in the word school are there?

a) 1440
b) 720
c) 360
d) 120

Since the question asks for arrangement, it means order MATTERS here.

If you don't consider the duplication of 2 O's, then the total cases are:

6! = 720

However, we should eliminate the duplication cases of 2 O's:

Since for each arrangement, you can always switch 2 O's to create a duplicated case, for example, SCHOOL, you can switch the 2 O's but they are duplicated

So the final answer will be 720 / 2 = 360