superman22x
Golden Master
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I just got told by an engineering student at Illinois Institute of Tech that the answer is two. I told him to drop out now before it's far too late.
if you actually followed what you wrote verbatim then you'd have gotten 2. (which is the problem)PEMDAS
Parentheses
Exponent
Multiply
Divide
Add
Subtract
The Correct Answer Is 288
How about a proof?
48
--- * (9+3) = 288. Solve for x.
x
Step one, simplify.
48*(9+3)=576
576/x = 288.
576/288 = x.
x = 2.
Do the same thing but set the equation = 2.
48
--- * (9+3) = 2. Solve for x.
x
576/x = 2
x= 576/2
x = 288
So, if the answer was 2, the equation would look like
48÷288(9+3) = 2
And for those that think division should come before multiplication or vice versa, take a look at this:
48/2 = 48*(1/2)
For those that aren't clear with the reasoning - the key here is that operators of equal precedence (so divide, multiply and similarly for addition, subtraction) are evaluated left to right. Despite what PEMDAS, BODMAS etc. would have you think the D/M and A/S are actually on the same level. Apart from that as far as I know it's broadly correct.
So:
48 / 2 (9 + 3)
Brackets first, not much argument there. So we get:
48 / 2 * 12.
Since division and multiplication are of equal precedence we evaluate left to right, so the division comes first. We can thus rewrite the following expression like this:
(48/2) * 12
From then on it's easy, 48/2 gives us 24 and 24*12 gives us 288.
That's not the original equation.that's not a proof.
I can write the same proof for the answer being two
48
---------- = 2 solve for x
x(9 + 3)
48
------- = 2
9x + 3x
48
--- = 2 therefore x = 2
12x
all these proofs (which would both be valid) shows is that the equation is badly written, and that causes confusion.
the point is unless the equation is re-written to be clear, then there is no real correct answer, there is a set of answers that are possible, numbers given above just happen to show those
That's not the original equation.
Whenever I write out equations for problems I am solving, they are as simply written as the one of the firs page. There is really nothing wrong with it. If you are seeing it a different way, you are either making assumptions or looking at it wrong.