Question

How many ordered lists are there of two items chosen from seven? ordered lists

Answer 1

Since we want the order in which items are picked, we are talking about permutations and not combinations.
Using the permutation formula, our n becomes 7, because this is the total of subsets we have, while 2 is the one we are looking for (items).

Thus, to pick two items from seven, we have:

`^(7)P_2 = (7!)/((7 - 2)!)`

`= (7!)/(5!) = 7 \cdot 6 = 42`

Thus, we have 42 ways to pick two items from seven if we wanted order.