300 posts!

[geodave]

Yes, the answer to the locker problem is all the square numbers. What this means, really, is that square numbers are the numbers that have duplicate divisors, and so end up with an odd number of toggles.

[rockdet]

Pretty much. We used to love fooling around with those at college

Also, I remember solving that problem last semester in my class

[geodave]

Hey, if you REALLY want to mess around, here's my favorite totally unnecessary math problem:

[BitBuster]

Oh my.

[Lessinath]

You like math aye?

Here are enough weather related formulas to keep you busy for a long time.

Know how to convert degrees F (T_F) and degrees C (T_C) to kelvin (T_K).

http://www.aprweathe.../pages/calc.htm

[geodave]

Actually, C and K are the same, except for the offset, so that's pretty simple.

My favorite process for going between C and F (and back) is the -40 rule. -40C = -40F. So, no matter what you start with, the three steps are:

1. Add 40

2. Convert units

3. Subtract 40

It is by far the easiest and it is exact. In the Midnight Oil song he says "The Western Desert lives and breathes at 45 degrees". Well that means nothing to me, so I add 40 (85), change units (85 * 9 / 5 = 17 * 9 = 153), subtract 40 is 113 degrees F. DAMN that's hot!

[geodave]

Problem: Break a 40 kg weight into 4 pieces such that those pieces can then be used to measure any (integer) weight from 1 to 40 kg using a balance.

Solution uses balanced ternary (digits: -1, 0, +1).

- Madhav.

Sorry to spoil this for others (not really!), but powers of three is the answer. You have to use a balance, of course, to do the measuring.

Nice problem, since there isn't really an equivalent in other bases.

[rockdet]

Also, just pointing out that I have 600 posts, which is twice the title of this topic.

I like those maths.

[geodave]

Also, just pointing out that I have 600 posts, which is twice the title of this topic.

I like those maths.

Perhaps it is you who needs to buy a life??

[BitBuster]

My favorite process for going between C and F (and back) is the -40 rule.

I've never had a problem with the "multiply by 9/5, add 32" rule. Actually, I never heard of the -40 rule before...seems a bit inconvenient, with the extra step and all.