GRE prcatice question

[Art Vandelay]

I saw this problem in a practice GRE book:

a*b*c=3a+4b-1/2 c

Which is greater:
3*6*12, or 27?

What do you think the answer is?

[GreyWanderer]

I don't understand? Are those two the same problem? I mean, it's obvious that 3*6*12 is greater than 27...

[Dorman]

Does * mean multiplication ?

[balrog666]

Originally posted by Art Vandelay

What do you think the answer is?

Time to buy a different book!

[Art Vandelay]

Originally posted by Dorman
Does * mean multiplication ?
Very good! You're on your way to figuring it out! You see, this is one of those symbolic questions. The first equation isn't a statement about a, b, and c. It's a definition of what "*" means. My sister said that the GRE doesn't use the asterisk for multiplication, so it really isn't confusing for them to create an entirely new meaning for it. Never mind that in certain circles, an asterisk is synomynous with a cross or dot. Seems like redefining the carrot to me. I hope nothing like this is actually on the GRE.

"GRE for Dummies" indeed.

[Zep]

They had better restate their problems to be much more clear what their intention is. I doubt there's many school-age children who haven't been exposed to "software programming". Consequently there will be a "society-specific" automatic understanding of what the statement is about that's different (and not correct) from what is actually intended.

Let me suggest this modification:

If a*b*c is calculated as 3a+4b-c/2

Which is greater: 3*6*12, or 27?

[GreyWanderer]

I don't understand anything, and I'm going to take the GRE this year. I'm getting worried now.

[Art Vandelay]

Originally posted by Zep
They had better restate their problems to be much more clear what their intention is. I doubt there's many school-age children who haven't been exposed to "software programming". Consequently there will be a "society-specific" automatic understanding of what the statement is about that's different (and not correct) from what is actually intended.

Let me suggest this modification:

If a*b*c is calculated as 3a+4b-c/2

Which is greater: 3*6*12, or 27?
No, that doesn't really change it. Maybe if they said "for all a, b, c ..." or "The asterisk is defined as being a symbol such that..."

[T'ai Chi]

Originally posted by Art Vandelay
No, that doesn't really change it. Maybe if they said "for all a, b, c ..." or "The asterisk is defined as being a symbol such that..."

The asterisk, or a filled in circle, is regularly used as a symbol for an 'operator'.

[pupdog]

I showed a colleague a graph that had "32 - s*10" on it (explaining a curve) and he kept looking for the footnote.

[epepke]

Originally posted by Zep
They had better restate their problems to be much more clear what their intention is. I doubt there's many school-age children who haven't been exposed to "software programming". Consequently there will be a "society-specific" automatic understanding of what the statement is about that's different (and not correct) from what is actually intended.

Let me suggest this modification:

If a*b*c is calculated as 3a+4b-c/2

Which is greater: 3*6*12, or 27?

Or "defined" or use the definition symbol (three horizontal lines) instead of the equals symbol.

I think the problem should be stated like this, presuming this Unicode thingie works:

a⊕b⊕c ≡ 3a+4b-c/2

[Lucky]

I suppose it means:
Take a number triple a,b,c, and define * to be some operation such that, for this triple a*b*c=3a+4b-c/2. Which is greater: 3*6*12, or 27?

The answer is that they’re the same. Though we weren’t asked, * could be, for example:
(working left to right) multiply by the next number and divide by 2^(ordinal position of the previous number).

Strange puzzle.

What is GRE, by the way?

[epepke]

Originally posted by Lucky
What is GRE, by the way?

I think it stands for Graduate Record Examination. It's a standardized test that people take as part of getting into a graduate program in the US.

[Thumper]

To answer the original question:

3*6*12 = 27, therefore one is not larger than the other.

As someone who took the GRE for entry into a non-technical field, the problem is acceptable.