<p>A teacher is to be assigned to teach 5 different courses in 5 different class periods on Mondays. If exactly one course meets each period, how many different assignments of courses to these class periods are possible on Mondays? Answer is 120 </p>
<p>I’m having trouble with permutations and combinations in general. I know that this answer is 5! , but only after reading the answer (120). How can i determine if order matters? Can someone please explain me this question + permutations and combinations in general??</p>
<p>The whole point is that order matters.<br>
There are 5 classes, each of which could be taught in 5 different period.
Period 1, you can assign one of 5 classes
Period 2, you have 4 remaining classes to assign
Period 3, 3 remaining classes, and so on.</p>
<p>You are talking purely permutations of those 5 classes. If you had to choose 5 our ot 6 or more classes, then you would be talking about comninations - and you would need to know if the question asked what combination of 5 classes, or what specific class schedule. In the question as stated, there is only 1 combination of 5 classes.</p>
<p>Assigning Math to Period 1 and English to Period 2 is different from assigning English to Period 1 and Math to Period 2. So the order matters, and this is a permutation.</p>
<p>Note that there are always more permutations than combinations. The two permutations I just described correspond to only 1 combination.</p>