Question: Bit of Everything

Comment on Bit of Everything

Hello, I am a little confuse. Why in the third step is written (16ˆ3/4) x (27ˆ2/3) and not (27ˆ2/3) / (16ˆ3/4). I follow the rule of 1/(a/b) = b/a. Thanks so much.
greenlight-admin's picture

The rule, 1/(a/b) = b/a, is correct, but we don't have a 1/(a/b) situation here.

I'm using the fact that (a/b)/(c/d) = (a/b) x (d/c)

Great, I was confused.Thanks so much for your explanation.

hello why did you multiply? and how did you get rid of 1 in 1/27?
greenlight-admin's picture

When dividing by a fraction, we multiply by the reciprocal.

That is: a/b ÷ c/d = a/b x d/c

So, for example: 2/3 ÷ 8/11 = 2/3 x 11/8

Likewise, (3/4)/(2/5) = (3/4)(5/2)

So, in the video solution, we have (16^something)/(1/27^something)

Applying the rule for dividing by fractions, we get:
(16^something)/(1/27^something) = (16^something)(27^something/1)
= (16^something)(27^something)

More here:

Does that help?


yes, thank you!!

I GOT THIS RIGHT!! yay! I want to do well in the GRE!
Thank you Brent! These video lessons and practice questions are so useful!

greenlight-admin's picture

Nice work! Keep at it!!


So I thought it was B, but that's because I didn't see the negative exponent in the denominator. Very hard to see if you pause the video in the very beginning!!!!

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