EPTI put it in my school calculator both possible ways:
48\2 (3+9)
=2
And:
48
---- (3+9) = 288
2
A Simple Math Problem? - Page 62
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strills
Australia27 Posts
I put it in my school calculator both possible ways: 48\2 (3+9) =2 And: 48 ---- (3+9) = 288 2 | ||
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FindMeInKenya
United States797 Posts
Anyhow, unless you never take elementary math, you would know there's only one answer to this question: 288. I see this not as failure of the writer of the question, but as failure of proper education. User was warned for this post | ||
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kidcrash
United States623 Posts
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strills
Australia27 Posts
On April 08 2011 17:06 FindMeInKenya wrote: Hierarch trolls pretty hard right now, would anyone topple his domination in trolloing???!!! Anyhow, unless you never take elementary math, you would know there's only one answer to this question: 288. I see this not as failure of the writer of the question, but as failure of proper education. Not true, the writer failed to show how the algorithm was supposed to be done. | ||
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GizmoPT
Portugal3040 Posts
On April 08 2011 17:06 FindMeInKenya wrote: Hierarch trolls pretty hard right now, would anyone topple his domination in trolloing???!!! Anyhow, unless you never take elementary math, you would know there's only one answer to this question: 288. I see this not as failure of the writer of the question, but as failure of proper education. i bet u feel smart | ||
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reprise
Canada316 Posts
On April 08 2011 16:35 101TFP wrote: 2y = 2*y right? Having 2 terms written directly next to each other does nothing but leave the * out. So 2*(9+3) = 2(9+3) The only reason you think that the 2 should be muliplied with each number in the bracket individually is because usually it's something like (9x+3) in typical math questions in which case you would have to multiply 2 with each individually to solve the bracket. In this case however, you can solve the brackets by just adding the two numbers together, which removes the brackets, making it 48/2*12. You could also write it like this (48)/(2)*(12) if you want your brackets. Still 288, no argument necessary here. http://www.wolframalpha.com/input/?i=48/2(9+3) http://www.google.de/#hl=de&source=hp&q=48/2(9+3)&aq=f&aqi=&aql=&oq=&fp=a175e2da902f2e1b If you're going to argue notation, you can't simply create a multiplication symbol between the terms. It simply isn't there originally. xy = x*y right? So what is 1/xy? From the OP's third poll, the majority of people recognize 1/2x as 1/(2x). Only when they are confronted by the OP's problem do they have to reexamine it. The original equation is purposely sloppy, so yes, arguments will ensue, but don't pass off what you think is correct as fact. | ||
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realills
2 Posts
ab/c = a/c*b = 1/c*ab =ba/c = b/c*a = 1/c*ba. EG, 12= 8*6/4 = 8/4*6 = 1/4 * 8*6 = 6*8/4 = 6/8*4 = 1/4*6*8 The people who think that whether you multiply or divide first, or whether you start at the left, right, or somewhere else first, makes a difference in the final answer are wrong. The fact that they arrive at different answers when following different "orders" within multiplying/dividing is proof that they're wrong: it would imply the real numbers are not a field, but we know they are. Their confusion is that they can't consistently decide whether 9+3 is in the numerator and the expression is telling us to MULTIPLY by 9+3, or whether 9+3 is inverted, is in the denominator, and the expression calls for us to DIVIDE by 9+3. Order of operations doesn't resolve the question. All that matters is the syntax, so that we understand what the question is asking. The correct syntax when you want to divide by multiply terms, but use only one divisor operator, is to group them together inside parenthesis: 48/(2*(9+3)). That is not the syntax in this question, and the correct answer here is 288. Similarly, 1/2x actually reads as "one half x, one half times x" BUT it's even more likely with that example, than with this numerical example, that someone who wrote that syntax made a mistake and actually *meant* 1/(2x). If I were a tutor or teacher or reviewing some casual work I would certainly expect "1/2x" to have meant to be 1/(2x), but the technically correct reading is (1/2)x. So some mistakes people are making: The distributive property of multiplication CLEARLY states that the 2(9+3) is an entire term The distributive property does NOT tell us that (9+3)/2 is the same as (18+6). If you want to distribute in this problem, you have to use the two terms in the numerator, 48(9+3)=432+144, and then divide by 2 as the last step. You will get 288.There is a difference between 48 / 2 *(9+3) and 48 / 2(9+3). No, there is no difference, according to the syntax, between these two terms. However, one is much easier to misinterpret. 2*(9+3) is exactly the same as 2(9+3), but in this case, one is a better choice because it more clearly conveys what the question is asking; they are equivalent, though.2(9+3) is always 24 But (9+3)/2 is not 24. Division is not associative, so you cannot "move" the operator away from the 2--it needs to stick to the front of the 2, always. 1/2 is not the same as 2/1. Ultimately I agree that this is a failure of the writer (and that no one would seriously write this question this way). The syntax does give one correct answer, but the writer had multiple choices of how to write the question and chose the most misleading (though still technically correct) way. | ||
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mcc
Czech Republic4646 Posts
On April 08 2011 17:06 FindMeInKenya wrote: Hierarch trolls pretty hard right now, would anyone topple his domination in trolloing???!!! Anyhow, unless you never take elementary math, you would know there's only one answer to this question: 288. I see this not as failure of the writer of the question, but as failure of proper education. Hmm, who is trolling, did you actually read the arguments, seems that you did not. Yes people who have taken elementary math will say it is 288, people who have taken university math and understood what notation is will say that it depends on notation used. | ||
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rackdude
United States882 Posts
On April 08 2011 16:54 Enderbantoo wrote: Wrong, there is no difference between 2(12) and 2*(12) *Edit for clarity* I think he just showed you that some people (namely, those that wrote online calculators and even wolfram) have different notation preferences than you. And in the general sense x(y) is very different than x*(y) in typing shorthand because x*(y) usually means the dot product making it a vector operation instead of just a scaler operation. Obviously in many mathematical logic courses (I say many because notation varies a lot in logic) that could mean the truth values of 2 and 12. Are you trying to say that if 2 and 12 are true than your statement is true, or that the number is 24? Of course, that's a notation preference. At least from what I've seen a lot of math professors and researchers I've emailed use * for the dot product in emails. I could see it being different though. Just like how some teachers write a ni for such that while some point the ni downwards. Ask your high school math student and you'll probably get 50% telling you the symbol looks like a euro and 50% telling you it's a weird m, all because of the teacher's own writing convention. | ||
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VIB
Brazil3567 Posts
On April 08 2011 17:07 kidcrash wrote: If anyone on any serious engineering job wrote something like the OP did, he would be in very serious risk of being fired :pThe onus is on OP to make his math problem as unambiguous and clear as possible. If this were engineering and someone got the wrong answer I'd place more blame on the person who wrote the problem than the person who read and calculated it. | ||
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Jyxz
United States117 Posts
It is also interesting when WolframAlpha is sited by the people who think the answer is 288 they use different notation then the OP, but in fact when you put in the original notation WolframAlpha says the answer is 2. The same is true for when you ask it 1/2x vs 1/2 x, which btw adding a space is using different notation. Also to all the people who think they have to feel pain because people who think the answer is 2 are so stupid... you are the people who make me feel pain. Summed up... its ambiguously written, thats why this thread exists. Ironically two types of people will choose 2 as their answer... the very stupid and math majors. The people who find arithmetic hard but smart enough to do it will choose 288. Edit: Ahh I got owned, all the times I saw wolframalpha come up with 288 they used a / instead of ÷ I guess i got trolled by this link where I saw the ÷ used. http://img864.imageshack.us/f/wolfram.png/ | ||
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FindMeInKenya
United States797 Posts
I truly believe this confusing is caused by failure of the American (or western) education. I taught English and Math in Taiwan, and China in local elementary schools couple years back, and this type of question is frequently encounter in the 2nd grade exams and most would answer correctly. If you are arguing about the pre-imposed logic behind mathematics operation, then it's a totally different matter. As of now, there's only one answer: 288. | ||
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realills
2 Posts
On April 08 2011 17:14 Jyxz wrote: It is also interesting when WolframAlpha is sited by the people who think the answer is 288 they use different notation then the OP No, they don't. The exact notation used by the OP is linked here, and Wolfram arrives at 288: http://www.wolframalpha.com/input/?i=48÷2(9+3) http://www.wolframalpha.com/input/?i=48/2(9+3) http://www.wolframalpha.com/input/?i=48 divided by 2(9+3) | ||
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Snipinpanda
United States1227 Posts
http://www.google.com/search?hl=en&q=+48÷2(9+3)&nocalc=1 | ||
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MajorityofOne
Canada2506 Posts
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Sqalevon
Netherlands523 Posts
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FindMeInKenya
United States797 Posts
On April 08 2011 17:11 mcc wrote: Hmm, who is trolling, did you actually read the arguments, seems that you did not. Yes people who have taken elementary math will say it is 288, people who have taken university math and understood what notation is will say that it depends on notation used. Then why do we teach our children the answer is 288? Also, the op did not state any specifics, so we can only read it as is. | ||
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Liveon
Netherlands1083 Posts
Oh wait, there was no 'right' and 'wrong' was there? | ||
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space_yes
United States548 Posts
On April 08 2011 17:05 Enderbantoo wrote: The main problem here lies in the way people are treating the distributive property... They think there is a difference between 3*2(4+1) and 6*(4+1) 288 is the correct answer because what is being distributed is 48/2. A good definiton is this It does not say that to evaluate 2(4+1) you first do (2*4 + 2*1) it says that when you multiple something in parenthesis by a term (In this case, by order of operations the term that is multiplied is 48/2 because before the multiplication into the parenthesis the division must first be completed) and when you multiply the term into the parenthesis you can evaluate it as either 24(9+3) OR (24*9+24*3) However you cannot first multiply the 2 in before dividing by order of operations Yeah it's hilarious in the yahoo thread the asker picked the wrong answer. The question is designed to troll people by putting a fraction on a single line next to a variable and then omitting the parentheses. It's supposed to seem ambiguous and the point of the question is for you to correctly resolve the ambiguity. It wouldn't be very fun if the question were written as: (1/2)x = ? a) 1/(2x) b) 1/2x | ||
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VIB
Brazil3567 Posts
On April 08 2011 17:28 Liveon wrote: Yes there was, both 288 and 2 are wrong. "It depends" is right Put this on my facebook for friends and family to solve, only 2 were wrong and 8 were right. They actually knew the 'work from left to right' idea. Oh wait, there was no 'right' and 'wrong' was there?  | ||
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