Question

determine the number of possible permutations of two of the five vowels: a, e ,i, o, and u. List them all

Answer 1

ok, so this is a combinatorial problem

Answer 2

there are 5 vowels, and they're asking you to choose 2

Answer 3

okay so would it be 10?

Answer 4

yes, but you can definitely list them all

Answer 5

so I would just pick two letter like a and e and then list all the possible letters that can be combined with them

Answer 6

1. ae
2. ai
3. ao
4. au
5. ei
6. eo
7. eu
8. io
9. iu
10. ou

Answer 7

exactly

Answer 8

there is also a formula for this

Answer 9

http://en.wikipedia.org/wiki/Combination search for the words "Finally there is a formula which exhibits"

Answer 10

thanks so much!

Answer 11

well one second

Answer 12

so if they mean "combinations", then the answer is 10

Answer 13

however, if they mean permutations, that is iu and ui are different permutations, then the answer would be 20

Answer 14

since there are 5 possible letters for the first spot, and then 4 possible letters for the second spot. so 5x4 = 20

Answer 15

in that case, just take the 10 we listed, and reverse the letters for options 11-20

Answer 16

I think they're asking for the 20 different permutations. since "permutation" and "combination" have different standard meanings in math: http://en.wikipedia.org/wiki/Permutation

Answer 17

ooo okay

Answer 18

if they were asking for the 10 we listed, the problem should have said "list all the combinations", not permuations

Answer 19

so yeah, just take the list, and make sure you have one possibility with the letters reversed for each of the 10 listed

Answer 20

alrite thanks

Answer 21

yeah np, good luck!