OT - Gentle Puzzle for 2012

[OkiePC]

I don't think it was a very good question.

I disagree. I thoroughly enjoyed it. I might agree after I know the correct answer though...

 

[L D[AR2P#0.0]]

I don't think it was a very good question.

I agree in hindsight, you live and learn.

 

[KalleOlsen]

If one bother to divide by 3, I guess only one of the combinations gives a certain rest that will point to the correct answer.

Kalle

 

[L D[AR2P#0.0]]

I disagree. I thoroughly enjoyed it. I might agree after I know the correct answer though...

You may have missed post#30

 

[OkiePC]

EDIT: No, i didn't miss post #30...between meetings and interruptions, I just needed some radio silence for it to soak in.

Dang...so close...

Thanks for an excellent piece for practicing logical thinking.

Now Peter? Care to retract that "rookie" comment?

By the way, who won?

 

[L D[AR2P#0.0]]

Steve Bailey..

 

[OkiePC]

Steve Bailey..

He is one sharp cookie...helped me several times...

 

[L D[AR2P#0.0]]

Here's a link to original version of this puzzle which I came across many years ago.

http://mathforum.org/library/drmath/view/56854.html

 

[Steve Bailey]

I was first with the correct answer, but I made the assumption about the size of PLC input modules. In fact, I noted that if the modules were sixteen points, then the choice was between [5 kW, 10 kW, 49 kW] and [7 kW, 7 kW, 50 kW] with the second eliminated because that choice didn't include a unique "smallest" drive. Of course, like Paul I made a mistake adding and included [5 kW, 5 kW, 108 kW] in the mix, calling the sum of those values 128.

But I went a step further and noted that if you allowed for 8 point input modules there were two additional possibilities; [2 kW, 35 kW, 35 kW] and [2 kW, 7 kW, 175 kW]. That's when LD[AR2,P#0.0] responded with his alternative statement of the problem and I realized that 64 was the only duplicate sum of the ratings. I got lucky in that my unnecessary assumption pointed to the correct answer.

 

[OkiePC]

Oh Steve, quit being modest. I think I may have been 2nd place, and that's pretty darn good in this set of company in my opinion. Not sure how many of the gurus even saw the puzzle and had the time to try to solve it though. Pretty sure for the first time ever I came in ahead of Mr. Nachtwey...so I am gonna take pride in that...even a blind squirrel finds a nut sometimes...

Paul

 

[ndzied1]

can't have a fractional female

 

[Peter Nachtwey]

What makes this a rookie question ?

I have pointed out that you assumed the drives come in only certain sizes. The number of inputs used, as stated in the question, can be anything.

The problem was not stated correctly.

I solved this problem symbolically. I didn't have actual values for the 3 drive or the I/O count. Just symbolic formulas. I used wxMaxima. It would be interesting to see how others solved this problem if they tried.

 

[Steve Bailey]

It would be interesting to see how others solved this problem if they tried.

1. The integer factors of 2540 are 2, 5, 5, 7, 7
2. Out of those factors, there are eleven different sets of three as shown in post #26.
3. Of the sums of those sets of three, two set add up to the same value (64). The rest of the sets each add up to unique values.
4. Because the salesman had to come back for more information after determining what the sum of ratings was, that sum must have been 64.
5. Of the two sums equal to 64, one had two drives sharing the same value which was lower than the third drive. Thus that combination failed to satisfy the condition that "the smallest drive (singular) does not have encoder feedback". That leaves the other combination [5 kW, 10 kW, 49 kW] as the only one of the eleven possibilities that satisfies the conditions.

 

[OkiePC]

The problem was not stated correctly.

There was no error in the statement of the problem...only in our perceptions and approach.

The problem was intentionally stated in such a manner to make it a tricky one...that was the whole purpose, no?

 

[RussB]

The fact that there was a "Salesman" involved makes any and all logic null and void. The answer can be anything you want it to be. Just depend on the "Not to Exceed" PO value.