Math Problem

[Greg Truby]

I think you could try to open after each 3# combo as you worked your way through each 4# combo, so I agree that you could probably ignore them in the answer. Since combination locks would go CW,CCW,CW,CCW or vice-versa I'd think it would be * 2, not * 8. The Permut() formula is for sampling without replacement. However I would expect that numbers could be repeated, so wouldn't the answer be:

=Round(15*2*60^4/86400)

 

[Ken Puls]

I think you could try to open after each 3# combo as you worked your way through each 4# combo, so I agree that you could probably ignore them in the answer.

Just tried it to satisfy my curiosity (we have both here).

I took a legitimate 3 number combination, added a bogus first number, and dialed it as I would a 4 number combination safe, and it did work. Go figure. My understanding was that they were designed not to do that.

So, I guess I'm saying that you could definately ignore them in the answer... providing that all safes work the same, of course.

 

[Legacy 21301]

Since combination locks would go CW,CCW,CW,CCW or vice-versa I'd think it would be * 2, not * 8.

The Permut() formula is for sampling without replacement. However I would expect that numbers could be repeated, so wouldn't the answer be:

=Round(15*2*60^4/86400)

Agreed (both points and the formula).

 

[PaddyD]

{snip}
=Round(15*2*60^4/86400)
----------
Agreed (both points and the formula).
{snip}

disagree - formula is missing an argument

=Round(15*2*60^4/86400,0)

...& at 4,500 days, I'd probably opt for explosives.

 

[Legacy 21301]

disagree - formula is missing an argument

Picky.

 

[Greg Truby]

...formula is missing an argument ...

Guilty as charged. The only defense I can offer is that I'd stopped by the Lounge while I was waiting for Outlook to shutdown (which takes way too long IMHO) and had not planned to write anything, but got "drawn in". By the time I'd drafted my answer, Outlook had actually finished "synchronizing with the server", so I was in a toot to post, shut down and get home to some roasted chicken 'n' taters.