Question

If no digit appears more than once, how many 3 digit numbers can be formed from the digits 2,4,5,7,9

Answer 1

So how many different ways can you permute 3 numbers from a set of 5?

Answer 2

does order matter? if not than its a combination

Answer 3

Well it asks for 3 digit numbers, so I think the order must matter because 247 is a different 3 digit number than 274

Answer 4

if 2,4,5 is the same as 2,5,4 then its
\[\left(\begin{matrix}5 \\ 3\end{matrix}\right)\]

Answer 5

all it said is if no digit appeared more than once, I'm assuming order doesn't matter since 2,5,4 is the same as 5,2,4 bc each digit appears only once in both cases

Answer 6

without replacement is my take on it

Answer 7

"how many 3 digit numbers can be formed"

Answer 8

the logic goes, for me at least:

there are 5 ways to pick the first digit
there are 4 ways left to pick the second digit
and there are 3 ways left to pick the last digit

Answer 9

It's a permutation without repetition problem.

Answer 10

cool

Answer 11

yeah it's a permutation

Answer 12

Isn't it 5!/2!3!

Answer 13

That's combinations.

Permutations is 5!/(5-3)!

Answer 14

no thats a combination

Answer 15

5*4*3= 60

Answer 16

I tend to mix them up, lol