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exponents to exponents

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exponents to exponents

by deagez » Sun Nov 29, 2009 4:40 pm
Not going to post choices, this is from MBA.com practice test, I think the answer is wrong here. Let me know what answer u come up with please.

[2^(4-1)^2] / [2^(3-2)]
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by thephoenix » Sun Nov 29, 2009 8:30 pm
IMO 2^5 or 32
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by deagez » Sun Nov 29, 2009 8:51 pm
thats exactly what I thought, it makes perfect sense, but the OA apparently is 2^8.

I think this is in error. 2^5 is definitely correct
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by papgust » Sun Nov 29, 2009 9:03 pm
2^8 is absolutely correct.

[2^(4-1)^2] / [2^(3-2)]

[2^3^2] / [2^1]

2^9 / 2^1

2^(9-1) = 2^8
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by Stuart@KaplanGMAT » Sun Nov 29, 2009 11:55 pm
papgust wrote:2^8 is absolutely correct.

[2^(4-1)^2] / [2^(3-2)]

[2^3^2] / [2^1]

2^9 / 2^1

2^(9-1) = 2^8
I've always wondered about this situation.

(2^3)^2 is clearly 2^6

2^(3^2) is clearly 2^9

When it's simply written as 2^3^2 is the rule that you always start at the right and work your way backwards? Doesn't the expression need brackets to be unambiguous?

The Google calculator agrees with papagust!

When you use the Google Calculator to resolve 2^3^2 it automatically rewrites it as 2^(3^2).

Similarly, when you use it to resolve 2^3^2^2 it automatically rewrites it as 2^(3^(2^2)).

So, if Google is right (who dares question the mighty G?), 2^8 is the correct solution.
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