How do I find the indicated values of these?
a. xP1
b. xC2
Permutations and combinations?
xP1 is the number of ways in which you can take one item out of x items - and that's just x. So for example the number of ways in which you can take one item from 10 is going to be 10. It doesn't matter whether order is important when only one item is involved, but in general order IS important - so if you wanted xP2 where x=10, the answer would be 10 times 9 = 90.
xC2 is the number of ways you can choose two items out of x when order ISN'T important - and that's x! / ((2!) ((x-2)!)), which is just x (x-1) / 2. So if x=10, xC2 would be 45.