Poll: What is the answer to 48/2(9+3)?

[timeadept]

This problem illustrates exactly why the order matters. There is only ever one answer to a math problem (well as long as we're dealing with functions like this one anyways). I don't know what to tell you if you don't trust me, but i am 100% sure that you handle division and multiplication whichever comes first from left to right, as with addition and subtraction.

I put this into my TI-83 and it came up with 288 (and it ALWAYS will). If that doesn't convince you that what i said is true, then i cannot convince you.

But addition and subtraction can be done in any order aswell, x-y is the same as -y+x. You can flip them about and juggle them any way you want. The reason we are getting different answers from the expression OP posted is because there's disagreement on what this expression actually is, not because of what order multiplications happen in.

I guess you could do addition and subtraction in any order and get the same result, but i'm not sure (probably because i'm so tired)and i would recommend always doing them from left to right.

I've always used / to represent division, not to separate the numerator and denominator of a fraction. My calculator uses the symbol to represent division as well (TI-83+). If i wanted to use that symbol and get 2 as my answer i would write the equation as 48/(2(9+3)). At this point i would have to say that you are using / incorrectly if you are using it to separate the numerator and denominator of a fraction.

 

[Juggern4ut20]

I have to agree with others. I read it as 48/(2*(9+3)) getting 2. I thought this since the / did not specify whether the (9+3) was under the denominator or not. it's pretty funny that people who think it's 288 are so mad and pretentious.

 

[Link_to_Future]

Well this has been an entertaining read. I forget how passionately people can argue about something so banal.

I'll just repeat what has been said before because there really isn't a lot to say. The problem is poorly presented. When I first looked at it I saw 2 because I always make it a point to separate individual fractions by parenthesis as so:

(48/2)*(9+3)

It's clear and unambiguous. There is no argument about how it can be perceived. Without the first set of parenthesis or the multiplication sign, I see it as being in the denominator. Is that wrong? Apparently, and since I'm wrong I'm a bad person and a terrible student who should just flip burgers for the rest of my life. That's how it works, right?

If this were a math problem of any actual bearing to any situation then it would be framed slightly better. Yes, all of you who say its 288 are correct. Technically. But why this sense of superiority that I'm sensing from some of you? What good is it doing honestly?

/preachyrant

good explanation, exept for one part. whats so unclear about it?
X and / before - and +, always.basic rule, right?
stuff of the same class go from left to right.
if you jsut stick to that, rigerously. its not unclear at all. exept for the not actually putting down an x or a . ( multlipication = x = . )

But don't you see that at a glance it could be seen the other way? Can't you acknowledge the possibility that someone would just work it in their head real quickly without following that basic rule simply because they failed to see it in that manner?

On simple set of parenthesis would make it so that there was absolutely no way to argue it either way. That there was no way to perceive it incorrectly.

I realize that technically you are correct. I never denied that. I'm just saying that it would be just as easy to make this undeniably one way or the other.

Also, that really wasn't the main point of my post. I was more curious about why people were acting so...smug. I was really trying to figure out why that was necessary.

Oh wait...internet. Right.

 

[timeadept]

Thanks, i needed that... going to sleep now.

 

[captain_dalan]

If the (9+3) was intended to also be in the denominator, it should have been written as:

48/(2(9+3))

As it is written, 48/2(9+3) , the answer should be 288 as the bracketed expression is a multiplier.

The disagreements stemming from this wouldn't be because the math is challenging, but because the way it is written is not ideal.

That's just silly.

If you wanted it to be 48/2 times (9+3), then why would you not put a clear symbol between the 2 and the paranthesis? You only omit that if you count that as a single entity. It's much more reasonable to assume that since the multiplication symbol is omited between the two, they count as a single entity, as the denominator in the division. Any reasonable person I know would assume so, and would write it as "(48/2)*(9+3)" if they wanted to seperate them. That's pretty much how you do these things.

I apologize for my double post, should no one have posted between then and now.

Because multiplication symbol is omitted in math (most of the time) for simplification of writing; same goes in physics

 

[Taerdin]

I have to agree with others. I read it as 48/(2*(9+3)) getting 2. I thought this since the / did not specify whether the (9+3) was under the denominator or not. it's pretty funny that people who think it's 288 are so mad and pretentious.

You read it as having extra parentheses that weren't there? No wonder you got the wrong answer

A division symbol doesn't specify whether anything is in a denominator, it simply means divide what is on the left by what is on the right. For instance 1/4+1 is (0.25+1 = 1.25), not 1/5. It would only be 1/5 with the added meaning of the parentheses for instance if it was written as 1/(4+1), which explicitly states add 4 and 1 then divide 1 by the result of that division.

It's much more reasonable to assume that since the multiplication symbol is omited between the two, they count as a single entity, as the denominator in the division.

It might seem reasonable to assume that if you didn't know the rules of math for this situation, which would assume no such thing about a denominator in this case. It's plain to see this is the case if you use any kind of computational application/device to calculate the answer.

 

[robotam]

It's written in a way that could mean it is either (as it is badly written it can't be said if the (9+3) is on the numerator or the denominator).

 

[justnotcricket]

This seems to come down to whether you're using the PEMDAS system or the BODMAS system, that is, do you divide or multiply first. Since I'm apparently either old or we learn things differently here in NZ, I use BODMAS and get 288.

But yes, the problem is ambiguously written, not helped by the apparent shift in methodology??

 

[Juggern4ut20]

You read it as having extra parentheses that weren't there? No wonder you got the wrong answer

A division symbol doesn't specify whether anything is in a denominator, it simply means divide what is on the left by what is on the right. For instance 1/4+1 is (0.25+1 = 1.25), not 1/5.

I read it as i saw it and others saw it. By using 2(9+3) instead of 2*(9+3), it is implying that they are one entity, as in all under the denominator, which is how i read it. The confusion isn't in PEMDAS at all, it has to do with how you read the problem.

 

[Taerdin]

I read it as i saw it and others saw it. By using 2(9+3) instead of 2*(9+3), it is implying that they are one entity, as in all under the denominator. The confusion isn't in PEMDAS at all, it has to do with how you read the problem.

I agree that this isn't a pedmas problem but rather that people read the question wrong. They assumed that / is saying anything at all about whether something is in a denominator (it's not). Without parentheses it is implied that only the first number is in fact in the denominator, any other expressions after that are seperate.

 

[RowdyRodimus]

288 (48/2)x(9+3)= (24)X(12)= 288

 

[Eclectic Dreck]

But don't you see that at a glance it could be seen the other way? Can't you acknowledge the possibility that someone would just work it in their head real quickly without following that basic rule simply because they failed to see it in that manner?

And I think you have stumbled on precisely why the statement was written as it was. While there is absolutely no ambiguity, the statement is not immediately clear. If one forgoes the process of determining precedence they can easily arrive at the wrong answer. The question was intentionally written in such a way as to invite this very thing.

People aren't wrong or stupid if they get the wrong answer; the only lesson they might take away is that they probably ought to use the rules of precedence when presented with a math problem where the answer actually counts for something save internet points.

 

[Bobbity]

I'm amazed that so many people got 2. If this were equal to two, then the sum would be written as 48/(2(9+3)).
Admittedly though, it's a badly worded question.

 

[Bearjing]

Umm... 2(9+3) is the same thing as 2*(9+3). It's pretty standard so there isn't any point of writing in the *.

 

[Eclectic Dreck]

Because multiplication symbol is omitted in math (most of the time) for simplification of writing; same goes in physics

This is true, especially when dealing with variables. xy simply means x*y, x also means x*y. In general, one can link a variable with a constant in this way (3x, or 3*x) but never two constants (33 is interpreted as the number "33" rather than 3*3). 3(3) is, however, acceptable since you have an operand dividing the two that implies multiplication unless otherwise stated.

 

[XandNobody]

Well, it depends.

48
------ = 2
2(9+3)

However,

48/2(9+3) = 288

And you wonder why they always told you to show your work.

 

[robotam]

I read it as i saw it and others saw it. By using 2(9+3) instead of 2*(9+3), it is implying that they are one entity, as in all under the denominator. The confusion isn't in PEMDAS at all, it has to do with how you read the problem.

I agree that this isn't a pedmas problem but rather that people read the question wrong. They assumed that / is saying anything at all about whether something is in a denominator (it's not). Without parentheses it is implied that only the first number is in fact in the denominator, any other expressions after that are seperate.

No the question is deliberatly written in a terrible way, in order to spark arguement between interneters. If you are going to have a division you had better make it clear what is being divided.
You can't just assume they only want to divide by the first number. It is not implied either way. It does look like the 2 on the denominator is being multiplyied by the brackets. And it is impossible to tell which answer is correct.