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## Comment on

Expanding Expressions## ab < 0

bc > 0

QUANTITY A: ac

QUANTITY B: 0

GIVEN: ab is NEGATIVE and bc is POSITIVE

So, (ab)(bc) = (NEGATIVE)(POSITIVE) = NEGATIVE

Simplify left side to get: ab²c = NEGATIVE

Rewrite as: (ac)(b²) = NEGATIVE

Since b² must be positive, we can write: (ac)(POSITIVE) = NEGATIVE

This tells us that ac must be NEGATIVE

So, we get:

QUANTITY A: NEGATIVE

QUANTITY B: 0

0 is greater than a NEGATIVE number

Answer: B

Cheers,

Brent

Crazily, I saw this whole algebraic thing as two relationships, in which (A) is the toxic union of two people, a and b. It is toxic because their result value is less than zero (<0), so one of them two is the toxic potentiator. Then I see that b conjoined with c and had a positive result (>0), so a is the one that messes things up, and makes the end result negative. In a relationship of a and c nothing good can come out of it since it's got a included, so the result will be negative as well, being less than zero. Crazy, but it worked for my abstract mind. Advice: Stay away from a.

## Question link: https:/

Question link: https://greprepclub.com/forum/ab-0-bc-3666.html

Ha! Great reasoning!

Cheers,

Brent

## At 7:07, is that a typo?

## Good catch - thanks!

Good catch - thanks!

I'll fix that shortly.

Cheers,

Brent

## Regarding the 2nd question

## Question link: https:/

Question link: https://greprepclub.com/forum/x-is-different-from-zero-9213.html

That's perfectly sound reasoning.

Nice work!

Cheers,

Brent

## Hello Brent,

Please, can you explain a little more how did you get to know those values?

You mentioned the following in the solution:

"We already know that 72.42 = 72 + 42/100"

https://greprepclub.com/forum/gre-math-challenge-14-72-42-k-24-n-333.html

Thank you

## Question link: https:/

Question link: https://greprepclub.com/forum/gre-math-challenge-14-72-42-k-24-n-333.html

Let's do a few conversions from decimals to fractions:

0.5 = 5/10 (aka 1/2)

0.7 = 7/10

0.24 = 24/100 (aka 6/25)

0.86 = 86/100 (aka 43/50)

0.123 = 123/1000

0.811 = 811/1000

0.125 = 125/100 (aka 1/8)

So, we know that 0.42 = 42/100

Also, 72.42 = 72 + 0.42

= 72 + 42/100

Likewise, 13.549 = 13 + 0.549

= 13 + 549/100

For more on conversions from decimals to fractions, watch https://www.greenlighttestprep.com/module/gre-arithmetic/video/1066

Does that help?

Cheers,

Brent

## So In this case you assume

Thank you

## Here's a different approach:

Here's a different approach: https://greprepclub.com/forum/gre-math-challenge-14-72-42-k-24-n-333.htm...

Cheers,

Brent