Using a standard cell phone keypad, how many random words (just letters strung together) can be produced from the PIN 23579?

I think there's some room for interpretation on this. I'm going on the assumption that you must use those keys in that order (i.e. get a letter from the 2 key, a letter from the 3 key, etc.). I'm also assuming it can be jibberish or the question would be

*really*unfair. :-)If that's correct, this in essence, this is not really different than the dice problem. It only

*seems*different. But if you always think of these types of problems as a series of events, and a number of outcomes for each event, they actually do work the same.If you press 2, how many outcomes can you have with the letters. That is, how many possibilities? (A B or C, so 3). So that's your first event, hitting the 2 key.

The 2nd event is hitting the 3 key. How many outcomes of letters for the 3? Well, 3 again because there's 3 letters on there.

The 3rd event is hitting the 5 key. How many outcomes?

Then you hit the 7 key. How many outcomes?

Then you hit the 9 key. How many outcomes? (Careful on that one.)

So once you know how many outcomes for each event you have, you can again use your multiplication rule --> just multiple the outcomes of each event to get the final answer.

One hint on doing these: distinguish between "and" and "or." You have 5 events, so it's key 2 AND key 3 AND key 5, etc. The "or" is the outcomes. Key 2 has 3 outcomes - A OR B OR C. If you write the "and"s across the top in a row, and then put the number of outcomes right below each, it's those outcomes you're going to be multiplying. Don't ever multiply outcomes times events.