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# What's the answer to this equation?

 View Poll Results: The answer is... 2 101 42.08% 288 139 57.92% Voters: 240. You may not vote on this poll

04-07-2011, 04:38 PM
#101
Leo Getz
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Quote:
 Originally Posted by My Sweet Shadow The issue then is what does 2(12) mean? If you're going solely based on mathematics, with no knowledge of common conventions and shorthands, there is no operator, thus there is no operation. If anything, that notation in math would be "2 as a function of 12" which makes no sense in this context. 2(12) could mean 2+12 as much as it could mean 2*12. The only reason that statement seems ridiculous to us is because 2(12) is a common shorthand of 2*(12).
But that still means when you take it as (48 / 2)(12) there is still no operation in between the brackets.

I think the tricky part of it is that it tricks your mind into thinking 2(12) is one term (regardless of the operation that is assumed).

Our brains look for patterns. At least for me when i first look at a division i put it into a fraction form, so i look for the numerator and denomenator. 2(9+3) looks like one term, and as such becomes my denominator.

04-07-2011, 04:39 PM
#102
Zaide
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Quote:
 Originally Posted by ThaDevilGirl Hum yeah, I got two but only 2 divides 48 so the real answer should be 288 or whatever it was.. Me But the Bedmas/whichever rule is a little dumb because division doesn't take precedence over multiplication, or addition over subtraction. Just have to go from left to right.
Also, in French we use PEMDAS if I remember correctly. That's what I learned.
"Parenthèse, Exposant, MULTIPLICATION, DIVISION, addition, soustraction"
This would mean that if we do this in order, the answer would be different for both french and english speaking people. You just have to do the multiplications and divisions in the order they come.

Quote:
 Originally Posted by QcnARF No 42 is the answer to a much bigger question (still don't know which one unfortunately). 288 here
Answer to life, the universe and EVERYTHING.

Last edited by Zaide: 04-07-2011 at 05:55 PM.

04-07-2011, 05:00 PM
#103
Agnostic
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Quote:
 Originally Posted by jbeck5 you typed in 24÷2(9+3)...you would get 2. I tried it on 5 calculators. The reason you're getting 288 is because you're not solving the brackets properly. You solve a bracket my multiplying what's in it right away with the number beside it. Example: 2(4) would switch to 8...not 2*4. In the first step, you're supposed to eliminate that 4 by multiplying it. Therefore 2(9+3) doesn't switch to 2*12...but to 24. In this equation,the 2 is connected to the 3 and 9 right off the bat, but not the 24 at the start.
Dude, do you operate a Disaster Planning company? talk about redundancy. Who the hell has 5 scientific calculators laying around.

Quote:
 Originally Posted by Ohashi_Jouzu I guess I'm wondering why the "shorthand" notation for the multiplication DOESN'T imply that the 2 is meant to be applied to the brackets it's "shorthandedly attached" to before applying order of operations to the less ambiguous rest of the equation. Sloppy notation for sure, but I guess the option is there to place another set of parentheses around the whole 2(9+3) if 2 is meant to be the answer, so I'll throw my hat in with the 288 crowd.
This.

If written properly the equation is 48/2*(9+3) and it becomes clearer.
If would be 2 if the equation was written 48/(2*(9+3))

 04-07-2011, 05:16 PM #104 SouthernHab Not a Fanboy   Join Date: Mar 2011 Location: USA Country: Posts: 12,854 vCash: 500 The Leafs and the Bruins suck equally.
04-07-2011, 05:20 PM
#105
HabsSlappy
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Quote:
 Originally Posted by Emanresu Wen Please mods, leave this unmerged for a couple of hours, would be nice. So there is this one equation that has been posted on many big internet forums and exactly 50% say that it's a certain answer, the other 50% says it's another answer (over 2000 people polled). The equation is : 48÷2(9+3) So what's the answer to this problem?

I think it equals 2, here is why.

In algebraic terms you could re-write this equation as 48/X(9+3), where X=2.
Simplify and you get 48/12X

Substitute 2 for x and you get 48/24 = 2

Or if you want, you could think of it as distributing the 2 to each of the numbers in the bracket:
48 : 2(9+3) = 48/(18 + 6) = 48/ 24

Seems that everyone thinks that brackets means multiply, which is does, but to be correct it means that a common denominator has been factored out of the brackets. ie. 18a+6a=2a(9+3)

I think in grade 11 I would have gotten 288, but in my many many many math, algebra, calculus, differential calculus, fourier transform, imaginary number, etc classes.....it is second nature to take care of the inner brackets first, then the term just outside the brackets. Then again, most of my math involved letters and symbols, not numbers.

Last edited by HabsSlappy: 04-07-2011 at 05:30 PM.

04-07-2011, 05:22 PM
#106
Woland
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Quote:
 Originally Posted by QcnARF No 42 is the answer to a much bigger question (still don't know which one unfortunately). 288 here
it's the answer to the Ultimate Question of Life,the Universe and Everything......so he is correct.

this formula, being something, fits into the category of everything.

edit .just noticed Zaide mentioned that as well

04-07-2011, 05:23 PM
#107
Peter Puck
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Quote:
 Originally Posted by Leo Getz But that still means when you take it as (48 / 2)(12) there is still no operation in between the brackets. I think the tricky part of it is that it tricks your mind into thinking 2(12) is one term (regardless of the operation that is assumed). Our brains look for patterns. At least for me when i first look at a division i put it into a fraction form, so i look for the numerator and denomenator. 2(9+3) looks like one term, and as such becomes my denominator.
No you don't get "(48 / 2)(12)". There is no bracket around the 48/2 in the original expression. What you get is 48/f(12) where the function f is the constant function 2. You wouldn't write this as (48/f)(12). For example if f were the cosine function, 48/cos(12) would be perfectly clear and would not mean (48/cos)(12). As I said, using 2(12) to mean the function 2 evaluated at 12 is valid math notation and would give 24 as the answer.

 04-07-2011, 05:25 PM #108 louisboi514 Registered User     Join Date: Sep 2010 Location: montreal Country: Posts: 9 vCash: 500 ppl are applying distribution rule on the denominator, that's why they're getting 2 It goes: 48÷2*(3+9) 48 ---- *(3+9) = 24*(12) = 288 2 done.
04-07-2011, 05:27 PM
#109
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Quote:
 Originally Posted by Pierre Dagenais 48 -------- = 2 2(9+3)
Correct response.

04-07-2011, 05:31 PM
#110
Fergy22
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Quote:
 Originally Posted by louisboi514 ppl are applying distribution rule on the denominator, that's why they're getting 2 It goes: 48÷2*(3+9) 48 ---- *(3+9) = 24*(12) = 288 2 done.

correct response

http://www.wolframalpha.com/input/?i...%28+9+%2B+3%29

 04-07-2011, 05:36 PM #111 New York RKY Moderator Let's Go Rangers!     Join Date: Sep 2009 Location: Dirty Jersey Country: Posts: 12,243 vCash: 500 It's 2. The way I learned it was PEMDAS. P- Parenthesis E- Exponents M- Multiplication D- Divide A- Add S- Subtract Therefore, you do the (9+3) first because it's inside the parenthesis Then multiply it by the 2, and divide the 48 by the 24. __________________
04-07-2011, 05:37 PM
#112
louisboi514
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Quote:
 Originally Posted by Peter Puck No you don't get "(48 / 2)(12)". There is no bracket around the 48/2 in the original expression. What you get is 48/f(12) where the function f is the constant function 2. You wouldn't write this as (48/f)(12). For example if f were the cosine function, 48/cos(12) would be perfectly clear and would not mean (48/cos)(12). As I said, using 2(12) to mean the function 2 evaluated at 12 is valid math notation and would give 24 as the answer.
48/cos(12) vs 48cos/12 ????
That is a bad analogy man. You can't possibly multiply a number by the term Cos... cos doesn't mean anything by itself. technically, 48/cos(12) can't logically be confused for 48cos/12 because cos(12) by itself is a number the same as saying 0.9781476.
You can't compare it with something like 2*(9+3), which is originally made with multiple independent terms

that being said the answer is 288

 04-07-2011, 05:38 PM #113 Emanresu Wen Registered User     Join Date: Apr 2010 Posts: 1,199 vCash: 500 oh god what have I done
 04-07-2011, 05:41 PM #114 Habs Registered User     Join Date: Feb 2002 Country: Posts: 9,798 vCash: 500 my god people, its 288, stop overdoing it.
 04-07-2011, 05:42 PM #115 Kboum Registered User     Join Date: Nov 2006 Location: Sherbrooke Country: Posts: 541 vCash: 500 answer is 2 braquets first
 04-07-2011, 05:46 PM #116 Bloumeister Live long & prosper     Join Date: Apr 2010 Location: location, location Posts: 7,449 vCash: 500 You can look at it any way you want, but the fact remains that the leafs are mathematically out of the playoffs run
04-07-2011, 05:47 PM
#117
Peter Puck
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Quote:
 Originally Posted by louisboi514 48/cos(12) vs 48cos/12 ???? That is a bad analogy man. You can't possibly multiply a number by the term Cos... cos doesn't mean anything by itself. technically, 48/cos(12) can't logically be confused for 48cos/12 because cos(12) by itself is a number the same as saying 0.9781476. You can't compare it with something like 2*(9+3), which is originally made with multiple independent terms that being said the answer is 288
Its actually a perfect analogy. I agree that 48/cos(12) can't be logically confused with 48cos/12. I wasn't claiming it can. In fact I was pointing out that it can't. I was only using cosine to illustrate proper math notation. I think it is clear the answer is 288 but I was agreeing with an earlier poster that 2(12) could denote a function evaluated at 12.

The symbol 2 is of course usually interpreted as a number but mathematicians also use it to denote a constant function. One needs to know the context to read the equation. Of course, in the absence of context, the most natural interpretation yields 288. But the other interpretation is also valid and yields 24.

Last edited by Peter Puck: 04-07-2011 at 05:57 PM.

04-07-2011, 05:49 PM
#118
knuck
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Quote:
 Originally Posted by Habs my god people, its 288, stop overdoing it.
indeed

48÷2(9+3) => 48 * 1/2 * (12) => (48 * 12) / 2 = 576/2 = 288

04-07-2011, 05:50 PM
#119
Kboum
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Quote:
 Originally Posted by knuck indeed 48÷2(9+3) => 48 * 1/2 * (12) => (48 * 12) / 2 = 576/2 = 288
gotta do multiplication before division

thats how I learned

 04-07-2011, 05:54 PM #120 Goldthorpe Meditating Guru   Join Date: Jan 2003 Location: Montreal Posts: 4,531 vCash: 500 it's 288. People think it's 2 because they translate the equation as: 48 ________ = 2 2*(9+3) But that's not right. The above equation would actually be: 48/(2*(9+3)) Which isn't the original equation at all.
 04-07-2011, 05:55 PM #121 Goldthorpe Meditating Guru   Join Date: Jan 2003 Location: Montreal Posts: 4,531 vCash: 500 Oh yeah, and 0.999... (repeating) = 1.0
 04-07-2011, 05:57 PM #122 HabsSlappy Registered User     Join Date: Jul 2005 Location: Ontario Country: Posts: 1,130 vCash: 500 I take back my answer......the correct answer is 8.67 48/2(9+3) = 48/18+6=2.67+6=8.67 Anyone on board?
04-07-2011, 06:00 PM
#123
knuck
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Quote:
 Originally Posted by Kboum gotta do multiplication before division thats how I learned
rofl

no. To multiply or to divide is the same. It's all about what you multiply/divide with. Same with addition and subtraction. To divide by 2 is to multiply by 1/2

Anyone who is even decent in math knows this. No offense but those who aren't sure just don't know the answer. There are quite a few people in engineering here, I'm pretty sure they will agree with my answer

04-07-2011, 06:00 PM
#124
Leo Getz
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Quote:
 Originally Posted by Peter Puck No you don't get "(48 / 2)(12)". There is no bracket around the 48/2 in the original expression. What you get is 48/f(12) where the function f is the constant function 2. You wouldn't write this as (48/f)(12). For example if f were the cosine function, 48/cos(12) would be perfectly clear and would not mean (48/cos)(12). As I said, using 2(12) to mean the function 2 evaluated at 12 is valid math notation and would give 24 as the answer.
I wasn't talking about functions. He said that you can't just assume 2(12) = 2*12. I was saying if you can't assume that, then you can't assume (48/2)(12) = (48/2)*12 either. I know there are no brackets in the original expression, I used them to show that the same thing can be said when you apply the division first. The fact that a(b) does not necessarily mean a*b but is only convention is irrelevant imo.

I also don't see how 2 can be a function as such, unless you define it. If you call two a function '2(x)', how do I know what happens at x. Why can't 2(x) = x or 2(x) = 2 or 2(x) = sin(x)+23. saying that the 2(12) to mean the function 2 evaluated at 12 is 24 only works if the function '2(x)' = 2*x

04-07-2011, 06:06 PM
#125
llamateizer
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Quote:
 Originally Posted by NYSportsfan6230 It's 2. The way I learned it was PEMDAS. P- Parenthesis E- Exponents M- Multiplication D- Divide A- Add S- Subtract Therefore, you do the (9+3) first because it's inside the parenthesis Then multiply it by the 2, and divide the 48 by the 24.

so 4 / 2 * 3 = 4/6 ????

http://www.mathsisfun.com/operation-order-pemdas.html

M and D must be done the same time from left to right

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