Solve 48

By webeagle12
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Stetson

Posted
Posted

and it makes no sense. also consider the following:

x / y(z)

x / y * 1(z)

according to those "rules" they would result in different answers.

I typed in x/y(z) and x/y*(z) into my TI-89, as well as the original equation:

post-182672-0-01135700-1302421498.jpg

So even though it acknowledges a difference between y(z) and y*(z), it still evaluates the original equation as 288.

I think the real issue here is the actual interpretation of the ? symbol. In most graphing calculators or applications I've seen, the use of the division symbol ? is replaced by a /. The / implies an over-under relationship like post-182672-0-32179500-1302418975.png or post-182672-0-10643300-1302418982.png. I've never seen the use of a linearly-written equation with a ? symbol like the original equation in any college level math course, I believe it's just bad practice. The existence of this thread is evidence as to why. ;)

Grand Master

primexx

Posted
Posted

It's TI ScreenCapture, part of the TI Connect software suite. You can connect the calculator via USB and grab screenshots from it.

Ah, from Stetson's picture seems like it's for the TI-89, which explains why i haven't seen it before :p

and wow that really puts the tiny resolution of the calculator into perspective!

Grand Master

sundayx Veteran

Posted
  • Veteran
Posted

post-182672-0-32179500-1302418975.png or post-182672-0-10643300-1302418982.png

This.

Edit: Actually the divide symbol defines that 48 divided by 2(9+3) so the answer is 2.

To get 288, the equation needs to be written as 48?2*(9+3).

Further readings:

http://physicsforums.com/showthread.php?t=488334

http://forums.macrumors.com/showthread.php?t=1134025

Grand Master

DigitalE

Posted
Posted

Ah, from Stetson's picture seems like it's for the TI-89, which explains why i haven't seen it before :p

and wow that really puts the tiny resolution of the calculator into perspective!

As far as I know, it works with any TI calculator with USB or a link port as long as you have the right hardware to hook it up (I think you need the TI GraphLink for the older calculators).

And yeah, the resolution is hilariously tiny :laugh:

Yeah, a TI calculator with a nice high-res E-Ink screen would be killer :D

I totally agree. They have some fancy new color LCD & WiFi ones, but an E-Ink one would be incredible!

Veteran

bogas04

Posted
Posted

according to BODMAS (Bracket Operation Division Multiplication Addition Subtraction) rule which was taught to us in small classes

i read it as 48/2(9+3) = 48 divided by 2(9+3)

2(9+3) is operation and not multiplication , so it will be done first , giving ans 2

Grand Master

primexx

Posted
Posted

This.

Edit: Actually the divide symbol defines that 48 divided by 2(9+3) so the answer is 2.

To get 288, the equation needs to be written as 48?2*(9+3).

Further readings:

http://physicsforums.com/showthread.php?t=488334

http://forums.macrumors.com/showthread.php?t=1134025

wow, reading those links just gave me a new appreciation of how awful people are at math...

e.g. a bunch of people think that the particular mnemonic they were taught (BEDMAS, PEMDAS) has to be done in that exact order,

and some idiots on the second link even think that without the multiplication sign, the stuff in the brackets are powers (wtf?)

edit: and even assuming 9+3 is a power, how the hell did they get 2 as the answer?!

As far as I know, it works with any TI calculator with USB or a link port as long as you have the right hardware to hook it up (I think you need the TI GraphLink for the older calculators).

And yeah, the resolution is hilariously tiny :laugh:

I totally agree. They have some fancy new color LCD & WiFi ones, but an E-Ink one would be incredible!

too bad the fancy colour one still has abysmal resolution

Veteran

leedogg

Posted
Posted

48/2(9+3) = 48/2(a+b) = 48/(2a + 2b)

NOT 24(a+b)

The answer is 2 based on the distributive law of multiplication taking precedence. If you want to know how PEMDAS factors in, you can just say that the digit next to the parentheses directly acts on the elements within the parentheses and therefore it's factored in before the rest of the order of operations.

so..um as I mentioned earlier

Grand Master

Arkaic

Posted
Posted (edited)

first off i have not done mathematics in at least 6+ years. second what type of math depends. algebra, trigonometry, etc...

Edit: oops nevermind. i saw the divide sign as a plus.................... now it makes more sense. :laugh:

i was wondering why my answers were so different and were the divide sign came in...

Grand Master

The Teej

Posted
Posted

Correct answer is:

48 / 2 * (9 + 3)

= 48 / 2 * 12

= 24 * 12

= 288

You cannot multiply 2 and 12 because 12 is not in the denominator. Do not make such incorrect assumptions just because of the way the expression is written.

Of course you could argue

48 / 2 (9 + 3)

48 / 2 (12)

48 / 24

2

Seen as obviously the 9+3 comes first, but should really still stay in the brackets, hence 2(12) should probably come first before 48 / 2?

Mentor

Jebadiah

Posted
Posted

Of course you could argue

48 / 2 (9 + 3)

48 / 2 (12)

48 / 24

2

Seen as obviously the 9+3 comes first, but should really still stay in the brackets, hence 2(12) should probably come first before 48 / 2?

No because the expression is not 48 / (2 (9 + 3)).

The expression is 48 / 2 (9 + 3). (9 + 3) is in the numerator. Like I said above, do not make incorrect assumptions. If the brackets are not there, they are NOT there.

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