Sunday, January 29, 2012

NPR Puzzle 1/29/12 - The Line Up

Here's this week's NPR puzzle:
Write the digits from 1 to 9 in a line. If you put a plus sign after the 2, a times sign after the 4, and plus signs after the 6 and 8, the line shows 12 + 34 x 56 + 78 + 9, which equals 2003. That's nine years off from our current year 2012. This example uses four arithmetic symbols. The object is to use just three of the following arithmetic operations: addition, subtraction, multiplication and division, in a line from 1 to 9 to get 2012 exactly. The operations should be performed in order from left to right. There are no tricks to this puzzle. Can you do it?
Well, we think we can. We just haven't yet. Check back on Thursday...

If you solved it, I know you were smart enough to submit your answer at the correct NPR form.

It's me (Magdalen) again. Ross did a wonderful job filling in for me while I was away in Maine for my MFA program, and then I got even more time off thanks to the Twenty-Fifth Anniversary gap last Sunday. But I'm glad to be back now. Of course I am. ;-)

Photos of numbers are easy; let's see if I can get some arithmetic symbols...and the answer is no (or at least I can't figure out how you find them). So here are some numbers, starting with 12:34:56 on 7/8/09:






I assure you, if any of those numbers are in the final answer, it's purely coincidental!

Time for...
This is where we ask you how many entries you think NPR will get for the challenge above.  If you want to win, leave a comment with your guess for the range of entries NPR will receive.  First come first served, so read existing comments before you guess.  Ross and I guess last, just before we publish the Thursday post.  After the Thursday post is up, the entries are closed.  The winner gets a puzzle book of our unspecified choosing.

This week, there were 580 entries; you were ALL winners, in one sense of the word. (In another sense, all but one of you were losers. Sorry.)  Alas, no one won the Pick a Range for last week. (I think. I reserve the right to edit this if I heard the number wrong.)

Here are the ranges:
Fewer than 50       
51 - 100
101 - 150
151 - 200
201 - 250
251 - 300
301 - 350
351 - 400
401 - 450
451 - 500

501 - 550
551 - 600
601 - 650
651 - 700
701 - 750
751 - 800
801 - 850
851 - 900
901 - 950
951 - 1,000
1,001 - 1,050         
1,051 - 1,100
1,101 - 1,150
1,151 - 1,200
1,201 - 1,250
1,251 - 1,300
1,301 - 1,350
1,351 - 1,400
1,401 - 1,450
1,451 - 1,500

1,501 - 1,550
1,551 - 1,600
1,601 - 1,650
1,651 - 1,700
1,701 - 1,750
1,751 - 1,800
1,801 - 1,850
1,851 - 1,900
1,901 - 1,950
1,951 - 2,000
2,001 - 2,050
2,051 - 2,100
2,101 - 2,150
2,151 - 2,200
2,201 - 2,250
2,251 - 2,300
2,301 - 2,350
2,351 - 2,400
2,401 - 2,450
2,451 - 2,500

2,501 - 2,750
2,751 - 3,000
3,001 - 3,250
3,251 - 3,500
3,501 - 4,000
4,001 - 4,500
4,501 - 5,000

More than 5,000
More than 5,000 and it sets a new record.
Our tie-break rule:   In the event that a single round number is announced, AND two separate people picked the ranges leading up to and leading up from that round number, the prize will be awarded to whichever entrant had not already won a prize, or in the event that both entrants had won a prize already or neither had, then to the earlier of the two entries on the famous judicial principle of "First Come First Serve," (or in technical legal jargon, "You Snooze, You Lose").  And yes, this rule is most-likely obsolete but I just like having fine print. 

14 comments:

DaveJ said...

A mathematical puzzle and a non-trivial one at that ! Perhaps Will is looking for a way to gracefully exit after 25 years. Next week I am guessing they will announce "just over 100 entries this week" and not say how many correct entries they received.

Mendo Jim said...

Imagine that! Mr. NYT Crossword Puzzle, National Crossword Tournament, etc. actually prefers cryptics.

As for today, I am going to wait for Dr. Shortz to issue the necessary corrections to the challenge before I start to work on it.


If you follow his instructions you get 2663, not 2003. Interestingly, old calculators and even older pencil and paper will give you 2663, while Windows will give you 2003 (if you don't ask for subtotals along the way).

I know about prececedence of operations, BTW.

Not so gracefully, I'm afraid, DaveJ.

skydiveboy said...

MendoJim:
It won't matter in solving the actual puzzle, but I agree with what you posted.
I suspect less than 100 will get the correct answer.

David said...

One thing I found interesting is that if you changed his example just a little (using MDAS), you can get 2012. With parenthesis, it would be 2012 = 12+(34*56)+7+89, so he could have presented the puzzle as "Here is how to get 2012 using four symbols. ... Can you get 2012 using just three symbols?"

I did in fact find this easy (but I was a math major, so I don't know how well I can judge the difficulty of this puzzle. While recent low participation has forced me to abandon my standard range, I hope you guys are pessimists about the math/arithmetic skills of the listeners. I'll go with 501 to 550, please.

EKW said...

I thought this one was very easy. But since it is math, I will
guess there will be about 201-250 correct entries.

Note: One of your pictures does indeed provide a clue!

Curtis said...

I found that going with the simplest possible approach worked in solving this puzzle. And, being simple, I will keep my same range guess from last week: 351-400.

Dave said...

101 - 150, por favor.

Paul said...

401 -450, please.

Anonymous said...

Everyone is saying to go with the simplest way to solve it, and after quite literally 12 hours of work (spread across the last three days) I've about reached my breaking point. Little help please? Not asking for an answer (even though that would be amazing) but a good hint would be nice.

skydiveboy said...

The idea is to solve it yourself.

Anonymous said...

Which I'm attempting to do, but something to point me in the right direction would be much appreciated. Just a thought.

skydiveboy said...

+, -, x & ÷. These are all the clues you need. Easy as pi. Where's the accomplishment if we tell you how to solve it?

Curtis said...

@Anonymous: Unfortunately, the answer is so deceptively simple that any clue would give away the answer. It's so simple, in fact, that you'll be amazed once you get it. I was trying for complex answers before I saw that I was making it harder than necessary.

skydiveboy said...

1234-5-6+789=2012