48÷2(9+3)

[Jonnie]

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The whole thing about this question is math majors and engineers usually get 2 while other people get 288.
No offense to anyone but 2*(9+3) is different then 2(9+3) as the 2(9+3) is a parentheses in which it takes prioity over multiplication and division due to you have to simplify it before you can move to the next step.

Also no one has proved me wrong in solving the question by entering an "x" in as a variable?????

Don't worry jeffjones, I saw it exactly the same as you.

Electrical engineer here and did A LOT of calculus in University... this is how we usually solved the problem. The only way I would get 288 is if the operation was explicitly written -> 48 % 2 x (9+3). The parentheses usually takes precedence, but you rarely see this come up in problems (if at all). I mean, onc you hit University, your professor will tell you everything you learned in high school regarding math and chemistry is incorrect. (Like the flow of electrons!)

But yes, it's exactly as you say jeffjones, Math/Engineering majors will view it differently. Both answers are "correct".

 

[jeffjones]

This is worse than wrong.

Way to read half sentences!
The way my words were cut and pasted to change what I said you would make a great news reporter

But I'm done with this as I think I have proved my point as no one here that got 288 can prove their answer by answering 48÷2(x+3)=288 and have x = 9.

Yes Jonnie, thats the only thing I was trying to prove was in every math question both sides are equal no matter where you substitute the variable
But this is the ugliest math eqution I have ever seen.

Have fun all.

 

[Jonnie]

After some further thinking, I think I have a clean way to describe why this problem is fundamentally broken:

Problem: 48 % 2 ( 9 + 3 )

Let's make things easier and ignore the (9+3), it's unnecessary. We'll henceforth call it B. Which means B = (9+3).

Problem rewritten: 48 % 2B

Now before we "solve it", we can all agree this is no different than writing 48 % 2 x B. They are the SAME THING! Why's that? We don't have parentheses! So 48 % 2B = 48 % 2 x B.

If they are the same, then why does a different answer occur? Ah hah!

An excellent way to solve equations, we all learned as a child, is to write them out in fraction. Let's try this...

48
----
2B

oh wait... or is it...

48
--- x B
2

??? WHAT!? They're absolutely two different questions all of a sudden.

So in conclusion? It's a poorly written problem and needs parentheses to indicate which of the two fractions above the problem giver intended you to solve.

 

[El Zilcho]

But this is the ugliest math eqution I have ever seen.

48/2(9+3) is not an equation by itself. The problem is in evaluating an expression. Your idea with substituting x somewhere in it and making it into an equation by putting right hand side of 288 makes no sense, since you're still faced with the same problem of interpreting the left hand side.

Also, 2(9+3) is same as 2*(9+3). A lack of operator is assumed to mean * and it's done only to de-clutter the writing of formulas.

While what you wrote may seem like you're getting somewhere, you're actually not making any sense.

 

[EngineerJoe]

So I can't sleep, so here I am again...

When you put the mutiplication sign behind the 2 you change the equation. I can change it too 48÷[2(9+3)]

The multiplication sign behind the two makes no difference. 48÷2(9+3) = 48÷2*(9+3) != 48÷[2(9+3)]. The lack of the multiplication sign between the "2" and the bracket does not imply additional brackets around that whole thing.

Like said before if someone can prove this 48÷2(x+3)=288 and have x = 9.
Then you can prove me wrong!
Because I can solve it like this 48÷2(x+3)=2 and have x = 9 ????

So let's re-write the equation so it's simplier to read
48÷2(x+3) = 48÷2*(x+3) = [48 * (x+3)] ÷ 2

Now let's equate and solve
[48 * (x+3)] ÷ 2 = 288
[48 * (x+3)] = 288 * 2 = 576
(x+3) = 576 ÷ 48 = 12
x = 12 - 3 = 9
x = 9

There you go.

 

[ike]

That would have made it too obvious

touche!

 

[ike]

When you put the mutiplication sign behind the 2 you change the equation. I can change it too 48÷[2(9+3)]

It seems to me that your expression "48÷[2(9+3)]" is a very different expression than 48÷2(9+3) You have added an extra level of grouping that has changed everything. Inserting an implied operator such as 48÷2x(9+3) does not change the expression and it becomes a simple calculation in which BEDMAS leads to the answer of 288.

If you were inclined to add extra brackets for clarity, then BEDMAS would lead you to this expression: (48÷2) x (9+3)

 

[toybm]

Everytime I see these equation threads I'm amazed at how the human mind can complicate simple things. We've got people substituing 'x' and 'B' and all sort of things. It's like looking at someone trying to use The Theory or Relativity to solve 2+2.

 

[jeffjones]

So I can't sleep, so here I am again...


The multiplication sign behind the two makes no difference. 48÷2(9+3) = 48÷2*(9+3) != 48÷[2(9+3)]. The lack of the multiplication sign between the "2" and the bracket does not imply additional brackets around that whole thing.


So let's re-write the equation so it's simplier to read
48÷2(x+3) = 48÷2*(x+3) = [48 * (x+3)] ÷ 2

Now let's equate and solve
[48 * (x+3)] ÷ 2 = 288
[48 * (x+3)] = 288 * 2 = 576
(x+3) = 576 ÷ 48 = 12
x = 12 - 3 = 9
x = 9

There you go.

But once again it is solved incorretly.

say this just so people can't find other ways to manipulate the equation to their

if (9+3) = x

then 48÷2x is the equation, not 48÷2*x as you say and can just break up the 2x whenever you want? That is a parentheses and remember in PEDMAS that is the 1st thing you have to do.

 

[Teal]

Here's another one for you Jeff...

Simplify the following into lowest terms...

7/(4-(16^(1/2)))

 

[caboose56]

Here's another one for you Jeff...

Simplify the following into lowest terms...

7/(4-(16^(1/2)))

*prepares for impending universe explosion*

 

[slogan]

That's all BS.*
You all try to reinterpret the equation, by putting "x" or whatever.*
the equation as it is "48 divided by 2 multiplied by sum of 9 and 3"*

 

[Sushii]

That's all BS.*
You all try to reinterpret the equation, by putting "x" or whatever.*
the equation as it is "48 devided by 2 multiplied by sum of 9 and 3"*

and whats your answer?

P.S Its not as it is because there are certain rules you have to follow. you can't always go from left to right.

 

[jeffjones]

That's all BS.*
You all try to reinterpret the equation, by putting "x" or whatever.*
the equation as it is "48 divided by 2 multiplied by sum of 9 and 3"*

How is adding an "x" to represent a variable in the equation BS, Its the most effective way of checking your answer?
In any mathematical equation you can add an "x" into any variable and have "= the answer" at the end and x will equal the that variable, hat was taught to me in public school and it has never been wrong?
Not being able to add the "x" and have the equation stay true like everyone getting 288 is BS lol

You are correct about this "48 divided by 2 multiplied by sum of 9 and 3" if it was a word problem written like this then 288 would be correct but it is not written that way

 

[slogan]

:sign3:

 

[slogan]

How is adding an "x" to represent a variable in the equation BS, Its the most effective way of checking your answer?
In any mathematical equation you can add an "x" into any variable and have "= the answer" at the end and x will equal the that variable, hat was taught to me in public school and it has never been wrong?
Not being able to add the "x" and have the equation stay true like everyone getting 288 is BS lol

You are correct about this "48 divided by 2 multiplied by sum of 9 and 3" if it was a word problem written like this then 288 would be correct but it is not written that way

Because if you want:
48 divided by 2 multiplied by sum of X and 3 in brackets, where X is equal 9 - won't change anything
or
48 divided by 2 multiplied by X, where X is equal sum of 9 and 3 - this doesn't change anything either

If you wanna say "48 devided by 2X (two X)" this sequence is not equal to the initial equation :la:

 

[Sushii]

Lets just end this discussion stating that both answers are correct. If you use PEDMAS its 2, if you bed BEDMAS its 288. The fault lies in the question itself.

/thread

 

[slogan]

+100

 

[jeffjones]

Lets just end this discussion stating that both answers are correct. If you use PEDMAS its 2, if you bed BEDMAS its 288. The fault lies in the question itself.

/thread

We have a winner!

 

[Splash]

In post #42 you wrote

But I'm done with this as I think I have proved my point ...

and now it's post 59 and you wrote

We have a winner!

I thought you were done?

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