DS - GMAT Prep - Practice Test - Arithmetic Operations

[Misha]

If the operation (triangle symbol - using ^ for this example) is one of the four arithmetic operations addition, subtraction, multiplication, and division, is (6^2)^4 = 6^(2^4)?

(1) 3^2>3
(2) 3^1=3

The answer is A, but I can't figure out why. I can figure out why B is SUFF, but maybe my reasoning is wrong since I can't figure out A.[/list]

[Khalid]

If the operation (triangle symbol - using ^ for this example) is one of the four arithmetic operations addition, subtraction, multiplication, and division, is (6^2)^4 = 6^(2^4)?

(1) 3^2>3
(2) 3^1=3

The answer is A, but I can't figure out why. I can figure out why B is SUFF, but maybe my reasoning is wrong since I can't figure out A.[/list]

With statement 1:

this function can only be addition or multiplication

with either of these two operations the left side does indeed equal the right...sufficient

With statement 2

this function can be either multiplication or division

with multiplication the left and right side equal one another

with division it doesn't...

hence 2 is insuffcient.

[Misha]

Ahh, I get it. I was thinking that the operation could only be one of the 4 arithmetic operations, rather than any combo of them if the math works out. I was taking a different meaning from the question. Thanks!

[RonPurewal]

If the operation (triangle symbol - using ^ for this example) is one of the four arithmetic operations addition, subtraction, multiplication, and division, is (6^2)^4 = 6^(2^4)?

(1) 3^2>3
(2) 3^1=3

The answer is A, but I can't figure out why. I can figure out why B is SUFF, but maybe my reasoning is wrong since I can't figure out A.[/list]

With statement 1:

this function can only be addition or multiplication

with either of these two operations the left side does indeed equal the right...sufficient

With statement 2

this function can be either multiplication or division

with multiplication the left and right side equal one another

with division it doesn't...

hence 2 is insuffcient.

extremely well done.

note the general takeaway here:
if you have a problem like this, in which a mystery symbol stands for one or more of a collection of operations, then your #1 goal is to figure out ANY AND ALL operations for which that symbol can stand.