Question

How many different strings can be made from the letters in ORONO, using all or some letters?

Answer 1

I need to know how to do this using combinations and stuff

Answer 2

Or maybe it's permutations.

Answer 3

rather a pain since you have to do it for one, two, three, four, and five

Answer 4

for 1 letter there are only 3

Answer 5

for 2 letters it looks like there are 7 different ones
OR
RO
ON
NO
RN
NR
OO

Answer 6

five letter strings are easiest, since there are \[\frac{5!}{3!}=5\times 4=20\] strings

Answer 7

i think this actually requires a bit of work for 3 and 4, although the answer is 13 and 20 respectively, so the total is 3+ 7 + 13 + 20 + 20 = 63
a tree diagram would be the best way probably

Answer 8

So, a tree diagram is the best way?