exponents

by **guest612** Sun Mar 16, 2008 3:02 pm

GMATPREP CAT 2:

#22 asks which value is greatest. According to the answer, (1/5)^(-2) is greater than 2^3. Can you please tell me how this can be?

by **StaceyKoprince** Mon Mar 17, 2008 4:29 pm

First, please make sure to post the entire text of the question, including answer choices. The test is adaptive, so this is only labeled #22 for you. #22 can be any problem in the entire database! :)

I can tell you, though, how to interpret the two numbers you gave me. Review your exponent rules (in the number properties book). Any number raised to a negative power is simply that number's reciprocal raised to the positive power. For example, 3^(-4) is the same thing as (1/3)^4.

So (1/5)^(-2) becomes (5)^2 which equals 25.
2^3 is only 8, so yes, the above term is bigger.

by **guest612** Mon Mar 17, 2008 7:24 pm

got it. Thanks!

by **StaceyKoprince** Wed Mar 19, 2008 4:42 pm

you're welcome!