48÷2(9+3)

48÷2(9+3) =

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Kuro said:
Do it by hand and give it a try.
Click to expand...

No problem:
1. 48 / 2 (9x +3) = 288
2. 24(9x + 3) = 288
3. 216x + 72 = 288
4. 216x = 216
5. x = 1

1. 48 / 2(9x + 3) = 2
2. 24(9x+3) = 2
3. 216x + 72 = 2
4. 216x = -70
5. x = -70/216
6. x = -35/108

What you and the others are confusing is that the 2 beside the brackets is just multiplication. It is not part of the brackets. Since it is multiplication it is at the same order of importance as division. Therefore we calculate the brackets first, then left to right doing the division first then the multiplication.

As Jones said above: Is the question 48 divided by 2 times x or is it 48 divided by 2x?
The question is 48 divided by 2 times x <<< because in bedmas or whatever, the division and multiplication are given equal importance, so you solve them as you read them left to right.
 
Sushii said:
But the problem is that different teachers use different ways to teach. Some teachers tell the kids that you always go from left to right when doing a multiplication and division question while some follow BEDMAS and do multiplication first.
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Still doesn't make sense... BEDMAS stands for Brackets, Exponents, Division, Multiplication, Addition, Subtraction.
Where in there does multiplication come before division?
The reality is they are given equal importance, as are addition and subtraction.
 
Diesel said:
Still doesn't make sense... BEDMAS stands for Brackets, Exponents, Division, Multiplication, Addition, Subtraction.
Where in there does multiplication come before division?
The reality is they are given equal importance, as are addition and subtraction.
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Sorry, meant to say the opposite. Division before multiplication. But either way, i believe the answer is 288.
 
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Sushii said:
But the problem is that different teachers use different ways to teach.
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No. The problem is that you're trying to "prove" your answer (i.e. your preferred ordering of arithmetic operations), using exactly that order. If you do the same thing in the same way twice, you are obviously going to get the same thing. The second attempt does not add any credibility to the first. This is exactly why converting the expression to an equation by putting an x in there does not prove anything.
 
El Zilcho said:
I already explained that. The original problem is in the ordering of arithmetic operations. In order to evaluate the expression you need to follow a certain order. In order to solve an equation based on the original expression you also need to follow a certain order. As long as the order you follow in both cases is the same, you are going to get consistent answers from both (even if the order of operations is wrong). Hence, you cannot use one to prove the other.

Doing so is like trying to "prove" Ohm's law with a multimeter. In reality, a multimeter only measures one quantity and calculates the others internally using Ohm's law.
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Exactly... inserting a x into the equation while still following the same interpretation of the order of operations will solve nothing. You will get the answer you expect because you are following the same operations.

So what it comes down to here is that we are debating the order of operations and it is how Jones said: Is the question 48 divided by 2 times x or is it 48 divided by 2x? << either way doesn't matter if you were taught that division and multiplication are of equal importance, and therefore you solve them left to right.
 
Sushii said:
But the problem is that different teachers use different ways to teach. Some teachers tell the kids that you always go from left to right when doing a multiplication and division question while some follow BEDMAS and do division first.

I've used BEDMAS all my life and its worked out great for me. Some people swear by PEDMAS and its worked great for them. So whos right?
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Sushii said:
So the answer varies depending on how you were taught in school. I was taught that multiplication was always done before division while some others were taught that they are equal so which ever comes first.
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How is Multiplication before division in BEDMAS they have and always will be equal. The problem with this question is that if the 2 is part of the parentheses or not, not if multiplication or division shoul dbe done first.
I have never heard a teacher say that multiplication comes before division, I belive you nust have misheard that somewhere?
 
jeffjones said:
How is Multiplication before division in BEDMAS they have and always will be equal. The problem with this question is that if the 2 is part of the parentheses or not, not if multiplication or division shoul dbe done first.
I have never heard a teacher say that multiplication comes before division, I belive you nust have misheard that somewhere?
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go 3 posts up.
 
Diesel said:
No problem:
1. 48 / 2 (9x +3) = 288
2. 24(9x + 3) = 288
3. 216x + 72 = 288
4. 216x = 216
5. x = 1
Click to expand...

But the thing that everyone is missing is it is not a case of multiplication or division first, It is you have to remove the parentheses the P in PEDMAS before you can move on, and since the 2 has to be factored through the parentheses.
even if you do the (9+3) you still have (12) (you cant just remove brackets when ever you want) which is still the parentheses as long as the 2 is beside it yes I under stand if it was (2)(12) then that is multiplication but it is not so the distributive property must be used to remove the parentheses before moving on to the division. If the 48/2 was written as a fraction (as it is not hence the divsion sign) then yes the whole 48/2 would have to be factored in through the (9+3).
 
Sushii said:
go 3 posts up.
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Thats just as bad lol, believeing that division takes precident over multiplication no matter where in the equation they are lol.

And thats why you think it is 288 ;)
 
jeffjones said:
But the thing that everyone is missing is it is not a case of multiplication or division first, It is you have to remove the parentheses the P in PEDMAS before you can move on, and since the 2 has to be factored through the parentheses.
even if you do the (9+3) you still have (12) (you cant just remove brackets when ever you want) which is still the parentheses as long as the 2 is beside it yes I under stand if it was (2)(12) then that is multiplication but it is not so the distributive property must be used to remove the parentheses before moving on to the division. If the 48/2 was written as a fraction (as it is not hence the divsion sign) then yes the whole 48/2 would have to be factored in through the (9+3).
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We'll have to agree that it is a poorly written question then. The way I take it is you do what is in the brackets first, not what is adjacent to the brackets - since that is just multiplication.

Did you ask your math prof to see what he thinks?

Scroll up and click my link to see this problem discussed on reddit. There are a lot of geeks there that explain better than I have why the answer is 288: http://www.reddit.com/r/WTF/comments/gmg8d/48293_wait_what/

Detailed explanation of this meme: http://knowyourmeme.com/memes/48293

[h=5]Standard Order of Operations[/h]If one strictly uses the standard order of operations to solve mathematical expressions, the answer to the problem would be 288, which is also the same solution provided by WolframAlpha[SUP][URL="http://knowyourmeme.com/memes/48293#fn17"][17]
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[/SUP] and Google.[SUP][18][/SUP]
By convention, the order of precedence in a mathematical expression is as follows:
  • Terms inside of Brackets or Parentheses.
  • Exponents and Roots.
  • Multiplication and Division.
  • Addition and Subtraction.
If there are two or more operations with equal precedence (such as 10÷2÷5 or 7÷2*9), those operations should be done from left to right.
Therefore, the problem “48÷2(9+3) =” would be solved like this:
48 ÷ 2 * (9+3)=
48 ÷ 2 * (12)=
48 ÷ 2 * 12=
24 * 12=
288
Click to expand...
[/URL]
 
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The way I got taught was BE(DM)(AS).

B - brackets (or parenthesis) - you resolve what is inside them, not what's touching them.
E - exponents
(DM) - division and multiplication get equal treatment, resolved from left to right.
(AS) - same goes for addition and subtraction.

As far as I was taught "2(3)" is identical in meaning to "2*3" and gets no special treatment for the fact that it was expressed using brackets. It is just plain old multiplication.

With that approach, the correct answer is 288.

Obviously some people have been taught otherwise - and that's ok too.
Their answer of 2 is correct, based on the rules they have been taught.

And really, the math is meaningless, unless it actually is representing something - in which case, the answer will be either right or wrong for the problem, regardless of the notation used to express it.

Is the word for that delcious fruit "apple" or "pomme" - maybe we should have a big debate and throw around our educational credentials to prove that french speakers are wrong just because english speakers don't use their word.
 
Diesel said:
http://www.reddit.com/r/WTF/comments/gmg8d/48293_wait_what/
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Wow, those guy must jerk off stale fish to gay p0rn lol.

I was told that BEDMAS was changed to PEDMAS as brackets and parentheses are slightly different, Parentheses is brackets plus anything associated with the brackets as in 2(9+3) would be a parentheses.
But in all honesty there will never be a definite answer unless stephen hawkings can type it into his computer!
 
El Zilcho said:
No. The problem is that you're trying to "prove" your answer (i.e. your preferred ordering of arithmetic operations), using exactly that order. If you do the same thing in the same way twice, you are obviously going to get the same thing. The second attempt does not add any credibility to the first. This is exactly why converting the expression to an equation by putting an x in there does not prove anything.
Click to expand...

You are right. I was under the impression that involving a variable would remind/show them that the 2 must expand into the brackets but I was mistaken.

Diesel said:
We'll have to agree that it is a poorly written question then. The way I take it is you do what is in the brackets first, not what is adjacent to the brackets - since that is just multiplication.
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I dont think this is a poorly written question. It seems to depend on how people were taught to interpret the question, and how people were taught order of operations.

Basically, I've read the links a bit more thoroughly and it seems the problem lies here.

"Many calculators and textbooks state that a higher value of precedence should be placed on implied multiplication than on explicit multiplication"
 
So then is (1+2)[SUP]2[/SUP] equal to 5 or 9?

Is the special treatment of numerals outside the parenthesis limited to multplication only?

Can you express the Pythagorean Theorum as "hypotenuse=(x+y)[SUP]2"?[/SUP]
 
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jolomatic said:
So then is (1+2)[SUP]2[/SUP] equal to 5 or 9?

Is the special treatment of numerals outside the parenthesis limited to multplication only?

Can you express the Pythagorean Theorum as "hypotenuse=(x+y)[SUP]2"?[/SUP]
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(1+2)^2 = (3)^2 = 9
Yes the exponent is tied into the parentheses.
(1+2)^2 is equal to (1+2)(1+2) correct?
Again lets throw an x in to solve for,
So if you were to put a division in there 18÷(x+2)^2 = 2


Your way:
18÷(x+2)^2 = 2
18÷(x+2)(x+2) = 2 << Notice it is all multiplication and division left but do you do the division first since your going left to right? Or do you finish the simplifying the exponent (ie. The Parentheses in the original question)
18/(x+2)*(x+2)/1 = 2
18 = 2

That doesn't look right to me lol

Other way:
18÷(x+2)^2 = 2
18÷(x+2)(x+2) = 2
18÷(x^2+4x+4) = 2
18/2 = (x^2+4x+4)
9 = x^2 +4x+4
5 = x^2 + 4x
0 = x^2+4x-5
0 = (x+5)(x-1)
Therefore : x = +1 or -5

Looks right to me?
 
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You Mathies need to relax a bit
 
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