A 4-digit password is a number that begins with a 3 and does not contain a zero or nine. If digits can be repeated, how many possible passwords are there?

Question

anonymous · Answer

$$8^{n}$$
8 digits and n=number of place holders.
$$8^{4}$$

anonymous · Answer

that doesnt make sence with the the answers provided.
1536
12
343

kamille · Answer

Well, do you agree that your password should look like this?

|dw:1361484207466:dw|

where x means a number?

anonymous · Answer

yeauhh.

kamille · Answer

So, you know, that there are digits:
0
1
2
3
4
5
6
7
8
9

Zero and nine can't be used, how many digits left?

anonymous · Answer

there's 8 left.

kamille · Answer

So, you know that digits CAN repeat, so where is "x" there can be 8 different numbers. So the soluttion:

|dw:1361485101288:dw|