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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://gre.myprepclub.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://gre.myprepclub.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://gre.myprepclub.com/forum/gre-math-challenge-14-72-42-k-24-n-333.html
Thank you
Question link: https:/
Question link: https://gre.myprepclub.com/forum/gre-math-challenge-14-72-42-k-24-n-333....
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
Help! I think my brain
Regarding the linked practice question (same as the one to which you linked above)
(https://gre.myprepclub.com/forum/gre-math-challenge-14-72-42-k-24-n-333.html)
Here is the prompt:
If 0 < n < 100
and
72.42 = k(24 + n/100),
then k + n =
I did the algebra, made the same deductions as those in your solution, and initially got the reportedly correct answer (i.e., k+n=17).
But then I noticed something that now has me confused.
From the given info, it seems that the value of k depends on the value of n.
So ...
1) If n = 90:
72.42 = k(24 + 90/100)
72.42 = k(24.9)
k = [72.42/24.9] = approximately 2.9
Then (k+n)=(2.9+90)= approx. 92.9
2) If n=10:
72.42 = k(24 + 10/100)
72.42 = k(24.1)
k = [72.42/24.1] = approximately 3
Then (k+n)=(3+10)= approx. 13
In case 1, (k+n) = 92.9
In case 2, (k+n) = 13
Am I missing something?
You're absolutely right!!
You're absolutely right!!
I just added a proviso to the question so that it has just one solution.
Check it out: https://gre.myprepclub.com/forum/gre-math-challenge-14-72-42-k-24-n-333....
So In this case you assume
Thank you
Here's a different approach:
Here's a different approach: https://gre.myprepclub.com/forum/gre-math-challenge-14-72-42-k-24-n-333....
Cheers,
Brent
Hey Brent what does in front
If Joe and Sue are in line to
If Joe and Sue are in line to get into a theatre, and Joe is IN FRONT of Sue, then that means Joe get into the theatre before Sue will.
So, here's one possible scenario: (Back of line)(other people)(Sue)(other people)(Joe)(theatre entrance)
Here's another scenario: (Back of line)(other people)(Sue)(Joe)(other people)(theatre entrance)