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Comment on Students at ABC Academy
After you get G, why not plug
Once we know that G = 60, we
Once we know that G = 60, we find the value of B by plugging G = 60 into an equation that relates both G and B. The equation 3G = 5B is such an equation.
To answer your specific question, we need to consider what G - 20 is. First off, it isn't even an equation; it's an algebraic expression that represents the number of girls remaining AFTER 20 girls leave. So, plugging G = 60 into that expression will just tell us that there are 40 girls remaining after 20 girls leave. This will not (directly) tell us the value of B (number of boys).
Hello, I am loving your
I did it like this:
(5x-20/3x-20) = 5/2; solve for x; x = 12
the answer will be 8x = 96
Perfect solution!!
Perfect solution!!
I started trying to do this
I'm not a big fan of the
I'm not a big fan of the approach of representing the boys and girls with 5x and 3x.
I feel there are a couple of potential pitfall that may occur on test day.
Here's the rationale that people use when applying this technique:
If we say 5x = number of boys
And say 3x = number of girls
Then the ratio of boys to girls = 5x/3x = 5/3
We get: (5x-20))/(3x-20) = 5/2
Solve for x to get: x = 12
The question ask us for the TOTAL number of children.
Since 5x = number of boys, and 3x = number of girls, the total number of children = 5x + 3x = 8x
So, we must evaluate 8x for x = 12
We get: 8(12) = 96
Does that help?
Cheers, Brent
im confused on how you get G
Start with: 2G + 60 = 3G
Start with: 2G + 60 = 3G
Subtract 2G from both sides to get: 60 = 1G
In other words, G = 60
More on solving equations here: https://www.greenlighttestprep.com/module/gre-algebra-and-equation-solvi...
Cheers,
Brent
Great, thank you!
How do you know that they are
It all comes down to verb
It all comes down to verb tense.
The first sentence tells us that the ratio IS (present tense) 5 : 3, which means this is the PRESENT ratio.
The second sentence, with IF and WERE, tells us about a HYPOTHETICAL scenario that COULD happen, which would change the ratio of students.
The last sentence asks, "How many children ATTEND (present tense) ABC school?"
So, the question is asking for the CURRENT (present) number of students. That is, we want to determine the number of students BEFORE any hypothetical changes occurred.
Does that help?
Cheers,
Brent
My approach was different.
Since we know the number students who attended ABC academy must be some multiple of (5+3=8), and then the remaining students after 20 girls and 20 boys had left will be some
multiple of ( 2+5=7). You'll realize its only the 96 that meets those conditions
Perfect approach - great work
Perfect approach - great work!!!
I just wanted to know if my
2x + 5x = x - 40 (this was pertaining to to the statement that 20 boys and 20 girls were to leave the school, along with the corresponding ratio of 2:5)
after solving for x i got 8, which i plugged back into each corresponding value to get 2(8)= 16 and 5(8)=40 that added up to 56, then i added the 40 back to the number of students that left to get 96.
It's hard for me to tell
It's hard for me to tell whether that solution is valid.
What does x represent?
Also, can you explain the steps you took to get the equation 2x + 5x = x - 40?
I have an interesting
Initially, the ratio is 5:3 and after subtracting 20 boys and girls, the ratio becomes 2:5.
Let x be the total number of students, so x-40 will be the number of students later (20 boys and 20 girls).
Since the number of students can't be fractions, x-40 should be divided by 7 (as the ratio is 2:5).
The only option E satisfies this condition. 96-40 = 56 which is divisible by 7.
Perfect reasoning!! Nice work
Perfect reasoning!! Nice work!!
Thanks Brent. :)
In this question once we get
All of that is correct, Ravin
All of that is correct, Ravin.
At the 1:16sec mark, the
The given information
The given information dictates how we write our ratios.
In the first sentence, the ratio is (# of girls)/(# of boys).
In the second sentence, the ratio is (# of boys)(# of girls).
So, that's the order in which we must create our ratios.
So, the ratios as they're presented is correct.
That said, the second sentence COULD have also said "If 20 boys and 20 girls were to leave, the ratio of the number of girls to the number of boys would be 5 to 2", in which case the answer to the question would still be the same, but the second ratio would look like this: (G - 20)/(B - 20) = 5/2
Does that help?
hey Brent, just so i
The 5x to 3x ratio represents
The 5x to 3x ratio represents the ORIGINAL number of students, whereas the 2 to 5 ratio represents the HYPOTHETICAL scenario after 20 boys and 20 girls leave.
Since the question asks for the ORIGINAL population, we must use the 5x to 3x ratio.
I am sorry if this is an odd
I would rate this question in
I would rate this question in the low Q150's.