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#585333 04/15/11 02:04 PM
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This question has been on a few other sites.

Your answer is.....


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Divot #585334 04/15/11 02:06 PM
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2?

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My mind tells me 288, but my heart says 2.

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4

cle23 #585337 04/15/11 02:13 PM
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Quote:

4




It is safe to assume you were not a math major.


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Divot #585338 04/15/11 02:14 PM
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It's 288

Order of operations.

In order of how to do it...

9+3 =12, so the problem becomes 48 divided by 2 times 12.

Next you'd do 48 divided by 2, so it becomes 24 times 12.

So it's



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I am pretty sure you take 48 divided by 2, which equals 24. Take 9+3, which equals 12, and then multiply the the two. So 24 times 12= 288.


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288

What do we get for doing your homework for you?


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Looks like you beat me to it.


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Divot #585342 04/15/11 02:19 PM
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It's poorly written so you have to make an assumption as to whether the 12 (from the 9+3) is in the numerator or denominator. If the former then the answer is 288; the latter, 2.

Order of operations has you do multiplication and division simultaneously. Division is, technically, multiplication by a reciprocal.

This is similar to having a sentence with pronouns where you can't determine to which subject the pronoun is referring. Depending on which way you go, the entire meaning could change.

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yes...288 it is...my bad...logic above is correct


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yup. 2

Divot #585345 04/15/11 02:22 PM
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I must admit I have been back and forth....

But I believe this is can be re-written as: 48÷2*(9+3) and order of operations would mean ( ) first and then division & multiplication in the order that they appear...so

288


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2*9 + 2*3 = essentially 18+6, so 24

48/24 = 2

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I agree, it should be 288 ... But it depends on who wrote the compiler.

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No, you have to do what is inside the ( ) first.

Parentheses
Exponents
Multiplication
Division
Addition
Subtraction

Please Excuse My Dear Aunt Sally.

This is honestly elementary school math.

No offense.



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Quote:

No, you have to do what is inside the ( ) first.

Parentheses
Exponents
Multiplication
Division
Addition
Subtraction




It's Mult/Div and Add/Sub on the same row I believe ... so if you come across a Multiply and Divide, they get the same prioriety and you have to go in order of left to right.

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You're right, but that's how I remember it lol.



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jc...

Again, order of operations does not mean that you work from left to right. It means that you first solve all terms within parentheses, followed by all terms that are raises to an exponential power, followed by all terms that are being multiplied and lastly all terms that are being added. The order in which you combine the terms within any one of those steps is assumed to be irrelevant. That is to say, 2 + 3 + 4 equals 9 regardless if you combine 2 and 3 to get the equivalent expression of 5 + 4, or combine terms to get 3 + 6, or 2 + 7.

This problem as written is simply ambiguous; it has two solutions that are the results of making one of two equally valid but mutually exclusive assumptions.

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google says it's 288.

man i am not even that far removed from some brush up classes on this, and it's crazy how easy you can forget.

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It does not have 2 answers. The answer is 288, period.

You do multiplication and division at the same time, in order, left to right.

Same with addition and subtraction.

That's what makes this 288 and not 2.



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This problem as written is simply ambiguous; it has two solutions that are the results of making one of two equally valid but mutually exclusive assumptions.




That pretty much sums it up. It needs another set of ( ) to remove the ambiguity.

edit....but if it was on a test, I would go with my answer earlier of 288.

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So what doers the colon do to the 3?

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That wasn't in the original question ... IDK who put that there in a reply lol.



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So what doers the colon do to the 3?




that depends on whether or not Richard Gere is involved.


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if you scroll up I think you will see who

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Oh! Too soon!

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Quote:

This problem as written is simply ambiguous; it has two solutions that are the results of making one of two equally valid but mutually exclusive assumptions.




Not sure it's ambiguous. 2(12) is 2 * 12 ... which is 48 / 2 * 12. Order of operations will go left to right when all operators are considered the same priority. If the 2 * 12 was meant to be in the denominator, it would have to be written 48 / (2(9 + 3)).

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No, you do not. Addition and multiplication are commutative, which means you can place the terms in any order and obtain the same result. There is no left to right convention in addition or multiplication; it's just a logical way of proceeding based on common practice.

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Quote:

ambiguous.





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Commutative property does NOT apply to division and subtraction. So you must go left to right.

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288

48/(2(9+3)) would equal 2.


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Quote:

This question has been on a few other sites.

Your answer is.....




Global warming

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Quote:

288

48/(2(9+3)) would equal 2.







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Commutative property does NOT apply to division and subtraction. So you must go left to right.




I understand that. That's why, without parentheses to define the order within the step, an assumption has to be made. Because division is, by definition, multiplication by a reciprocal and multiplication is commutative, you need something to define which terms constitute the reciprocal by which you're multiplying.

If you plug it into a calculator you're going to get 288, but that's because the calculator has to be programmed to operate in a linear fashion which has arbitrarily been decided upon but isn't based on a rule that must be followed.

Divot #585369 04/15/11 02:53 PM
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288.

48÷2 = 24

9+3 = 12

So .....

24x12=288


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Quote:



If you plug it into a calculator you're going to get 288




Plug it into a TI 85 and tell me what you get.


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you need something to define which terms constitute the reciprocal by which you're multiplying.



You do have something ... parenthesis ... which aren't there, so you do the division first.

Order of operations still applies when parsing, and you work left to right. Left to right *is* a rule. 2 - 1 + 1 is always 2, not sometimes 0.

Commutative property applies to the formula itself and NOT the order of operations. 2 - 1 + 1 will always go (2 - 1) + 1, unless redirected with parenthesis.

If you apply the Communative property you have to isolate each individual number and then change everything to an addition sign ... so: (2) + (-1) + (1) can be rearranged.

In the original: (48) * (1/2) * (9 + 3) can be rearranged.

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Excl, are you a programmer by chance?

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