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Addition error
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Fresh-Faced Recruit
Join Date: Oct 1999
Location: Buffalo Grove,IL,USA
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Oct 18, 2000, 12:54 AM
 
I cannot take credit for this challenge; it has probably been arounf for awhile, I've only recently been exposed to the problem. Use your "Calculator" desk accessory (I'm dating myself, I mean "Apple Menu Item"). Enter, in sequence, "1000+40+1000+30+1000+20+1000+10". What total do you get? Your silly old human brain gets "5000". The MacOS gets "4100". You can change some of the various integers, but you'll still get goofy answers. Can anyone tell me why? I'm not being smug: I have no clue.
     
Mac Enthusiast
Join Date: Sep 2000
Location: AB, Canada
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Oct 18, 2000, 01:16 AM
 
Originally posted by sef6:
I cannot take credit for this challenge; it has probably been arounf for awhile, I've only recently been exposed to the problem. Use your "Calculator" desk accessory (I'm dating myself, I mean "Apple Menu Item"). Enter, in sequence, "1000+40+1000+30+1000+20+1000+10". What total do you get? Your silly old human brain gets "5000". The MacOS gets "4100". You can change some of the various integers, but you'll still get goofy answers. Can anyone tell me why? I'm not being smug: I have no clue.
I get 4100 with my brain. Look at it like this, you have 4x 1000 which equals 4000. You also have 40+30+20+10 which =100. Therefore 4000+100=4100. You seem to like math riddles. Here is one for you. 3 guys order some pizza the hotel delivery boy tells them it will be $30.00. So each guy gives the hotel delivery boy $10.00. The delivery boy takes the money to the pizza place and is told the order is only $25.00. The boy decides to keep $2.00 for a tip because $5.00 does not divide equally into 3. The boy returns to the hotel with the pizza and gives back each guy $1.00. If each guy gave $10 and got $1.00 back means they must have paid $9.00 each ($10.00 -$1.00=$9.00) right. 3 x 9 =27. If this is true and boy kept $2.00. $27.00 +$2.00 = $29.00. They originally started with $30.00 but only $29.00 can be accounted for ($30.00-$29.00=$1.00) where did the other $1.00 go?

I know that this really belongs in the lounge because this is really not OS related.


[This message has been edited by crazycylon (edited 10-18-2000).]
As a man comes, so he departs.
     
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Oct 18, 2000, 09:18 AM
 
Ahhh, good one Crazycylon! You had me going there for a minute.

The answer lies in the fact that the $2 tip came out of the (3x9)$27, so to do the math we subtract 2 from 27, not add 2 to 27. So 3x9=27, minus 2 for the tip which leaves 25, the cost of the pizza. In summary:

$25 - cost of pizza
$2 - tip
$3 - change
_______________
$30 - total

Everyone's happy. Hope you don't mind me responding to this. I love a good brain teaser. I'll post one in the lounge when I get to it.
     
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Join Date: Jan 1999
Location: Norman OK US 73071
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Oct 18, 2000, 03:57 PM
 
Maybe your silly human brain gets 5000. I agree with the Calculator, I get 4100.

Maybe its the "New Math" you were taught. I learned mathematics the old-fashioned way.

------------------
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No combat ready unit has ever passed inspection. No inspection ready unit has ever passed combat. - Murphy's Laws of Combat
     
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Oct 18, 2000, 04:39 PM
 
Maybe it's "fuzzy math"?
     
TrevorZ
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Oct 18, 2000, 04:42 PM
 
The problem is that our brains can be easily fooled. When you add up the numbers _in the order_ you mentioned, the last mental addition is 4090+10 = ? Because we are doing the problem in our heads, we see the 90 + 10 and know that we should increase the hundreds by one. But since there are zero hundreds at the moment, we slip and increase the thousands, and get the wrong answer 5000 instead of the correct answer 4100.

As for the pizza problem, you should add the $2 tip to the $25 cost of the pizza, for a correct cost of $27, with $3 returned to the three purchasers. The problem sentence is this: >> If this is true and boy kept $2.00. $27.00 +$2.00 = $29.00.<< Why is the $2 being added to the pizza twice? It was already part of the $27 cost of the pizza.
     
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Oct 18, 2000, 06:08 PM
 
what? there's no "explanation" needed. some people just don't add properly, that's all.

-r.
     
   
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