When you encounter a Quantitative Comparison question, be sure to consider which strategy might best apply:
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Comment on Fraction with Many Operations
I don't get it. When you
Be careful. 59/124 - 8/15 is
Be careful. 59/124 - 8/15 is not equal to 8/15 - 59/124
If this were a sum, then it WOULD be true that 59/124 - 8/15 = 8/15 - 59/124
However, in the question we are dealing with subtraction.
Here's a different example: 5 - 1 does not equal 1 - 5
Does that help?
Cheers,
Brent
do i have the calculator
Yes, you will have access to
Yes, you will have access to an onscreen calculator on the test. It's pretty clunky though. Here's the video on how it works: https://www.greenlighttestprep.com/module/general-gre-info-and-strategie...
after subtract 411/811, I
Then, if we divide both quantities by (59/124 - 8/15) we get quantity A = 1 and Quantity B = -1
So, quantity A should be greater than B?
When you divide both
That's a great idea!
However, when you divide both quantities by (59/124 - 8/15), you are breaking a fundamental rule when it comes to the Matching Operations strategy (covered here: https://www.greenlighttestprep.com/module/gre-quantitative-comparison/vi...)
IMPORTANT: (59/124 - 8/15) is NEGATIVE
So, when you divide both quantities by (59/124 - 8/15), you are dividing both sides by a NEGATIVE value, which is not allowed.
Cheers,
Brent
How is 8/15 greater than 1/2
There are a few ways to show
There are a few ways to show that 8/15 is greater than 1/2
APPROACH #1 - number sense
7.5/15 = 1/2, so 8/15 must be greater than 1/2
APPROACH #2 - Use long division to convert each fraction to a decimal
1/2 = 0.5
8/15 = 0.53333.....
Since 0.53333 is greater than 0.5, we know that 8/15 is greater than 1/2.
APPROACH #2 - find common denominators
1/2 = 15/30
8/15 = 16/30
Since 16/30 is greater than 15/30, we know that 8/15 is greater than 1/2.
Cheers,
Brent
I did not think to simplify
My first step was to cancel out the 411/811 from QA and QB. I was left with
QA: [(59/124)-(8/15)]/1/3 and QB: [(8/15)-(59/124)]/5/15.
From there, I got
QA: [(59-8)/1860]/1/3 and QB: [(8-59)/1860]/5/15.
From there, I got QA: (51/1860)/1/3 and QB: (-51/1860)/5/15.
Lastly, QA: 51/1860 x 3/1 = 153/1860 and QB: -51/1860 x 3/1 = -153/1860.
Answer: QA is greater, QB is negative. Where did I go wrong besides simplifying the 5/15 to 1/3?
When dealing with 59/124 - 8
When dealing with 59/124 - 8/15, you were correct to rewrite each with the common denominator of 1860.
However, in doing so, you never changed the numerators (in order to create equivalent fractions).
Take: 59/124 - 8/15
Rewrite the fractions with common denominators: 885/1860 - 992/1860
Combine the fractions to get: (885 - 992)/1860
Simplify to get: -107/1860
You made the same error with all fractions.
Does that help?
Cheers,
Brent
For more on adding and subtracting fractions, watch: https://www.greenlighttestprep.com/module/gre-arithmetic/video/1069
I thought you'd have to
You COULD go that route, but
You COULD go that route, but it will take a while :-)
After canceling obvious
I think that's a totally
I think that's a totally legitimate solution, since it wouldn't take long to perform those calculations on the calculator.
Hey what i get confused is
and in 8/15 i did 8/16 so 8 by 15 will be greater as Denominator decreases so am i rigth in this appraoch....i learned it from u.....can u give me some tip/tips to be a bit sure for next time
Here's the key property to
Here's the key property to keep in mind in the future: If the 4 smaller fractions in one quantity are exactly the same as the 4 smaller fractions in the other quantity, there's no need for approximation. Instead you can try eliminating identical fractions.
For example, if you multiply both quantities by 1/3, you can eliminate 1/3 and 5/15 from both denominators.
My man Thank you~!!!