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48÷2(9+3) =


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My College Algebra teacher last year gave us this question and 288 was the answer. :p

 

See end of post #37. ;)

 

You do know that i live in "the best country in the world" (according to this article: http://www.newsweek.com/feature/2010...ountries.html#) ....

 

Well, Newsweek? That explains everything. :xp:

 

@Ray---well, when you put it that way......:D

 

@Phoenix--C&H rules.

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^apparently the rules are interpretted differently. That was the whole point. Problem with the problem was ambiguous notation.....or noone would be "arguing" about it at all.

 

People may interpret it two ways, but only one way is mathematically correct. That way being, Multiplication and Division (and Addition/Subtraction) have equal precedence and occur from left to right.

 

You could turn the division into a multiplication and multiply from left to right.

 

48*(1/2)*(9+3)

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Generally speaking, you're supposed to distribute the parentheses first and then do all the other operations. So..

 

48/2(9+3)

 

 

Distribute the 2

 

48/(18+6)

 

Add the parentheses and divide.

 

48/24 = 2

 

 

 

 

I know, I'm like every other person who solved this problem.

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Generally speaking, you're supposed to distribute the parentheses first and then do all the other operations. So..

 

48/2(9+3)

 

 

Distribute the 2

 

48/(18+6)

 

Add the parentheses and divide.

 

48/24 = 2

 

 

 

 

I know, I'm like every other person who solved this problem.

 

 

And tell me exactly how you came up with a made up math rule? :p JK. But I've never heard that... the only time I've ever heard of distribution is when there's a + or - sign in front of the number and parentheses due to the fact that it is multiplication and multiplication comes before adding or subtracting, but in the event that there's a division sign, you do the Parentheses, Exponents (if any) then multiply or divide (if the division comes first, you divide, but if multiplication comes first then you multiply first).

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Idk, that's what we did in pre-calc. For doing vertical or horizontal shifting to the standard y = mx+b formula, it's something like this:

 

y = m(x+5)+b

 

which then equals

 

y=mx+5m+b (if my math is right)

 

Then again, this equation isn't really written nicely..... the problem seems to be coming from whether the equation is

 

48

--------

2(9+3)

 

or

 

48

--- (9+3)

2

 

I'm inclined to think it was the former, because if they wanted to indicate that you should divide 48/2 first and then multiply that by (9+3) they would have separated the terms with parentheses. Just saying.

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I'm inclined to think it was the former, because if they wanted to indicate that you should divide 48/2 first and then multiply that by (9+3) they would have separated the terms with parentheses. Just saying.

 

 

But if they wanted you to do that, then I would think that they would have divided the equation better. They would have done 48/(2(9+3)). Rather than... 48/2(9+3)...

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  • 2 weeks later...

Do parenthesis first = 12

 

Now, here's the tricky bit, in maths, not having a sign between a number and a parenthesis indicates that you should assume there's a multiplication sign there. No ifs. No buts. Therefore, you do the division first, 48/2=24, then you multiply 24 by 12=288

 

I hate this equation, the problem with it is that when written online, it's difficult to differentiate whether it's putting 48 over everything, or 48 over 2 times the parenthesis. The correct answer is the latter

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2 or 288 is correct simply because the notation is impossible to understand. I'd tend to agree with the "288" people, but I think both sides have a valid argument.

 

The notation may be confusing in this form, but it's surely possible to understand. And only one answer is correct, 288 :)

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