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Comment on Working with Percent
I like the idea that one
"In group 1, there are 300
allergic wheezing and (0.02)(300) people, or 6 people, have nonallergic wheezing.
Therefore, in group 1, the number of people who have allergic wheezing exceeds the number who have nonallergic wheezing by 9, which is \frac{9}{6}=1.5*100%
The answer is C
I got 250% (not even an answer choice) because I did 15/6 *100 rather than 9/6 * 100. How do you know to do 15/6?
You're referring to the
You're referring to the question here: http://greprepclub.com/forum/the-number-of-people-in-group-1-who-have-th...
You're mixing up the fact that 15 is equal to 2.5 TIMES 6 with the concept of "greater than".
For example, we can say that 12 is 200% of 6, since 12 = 200% of 6 = 2.00 x 6
However, we can't say that 12 is 200% GREATER THAN 6
To find 200% GREATER THAN 6, we need to ADD 200% of 6 TO 6
That is, 200% GREATER THAN 6 = 6 + (200% of 6) = 6 + (12) = 18
It's best to think of "greater than" in terms of PERCENT CHANGE.
Percent change = (100)(difference if values)/(original value)
So, "x is what percent greater than y?" translates into:
(100)(x - y)/2
The original question is asking "15 is what percent greater than 6?"
So, the percentage = (100)(15 - 6)/6
= (100)(9)/6
= 150%
Dear Brent,
I hope you can clarify two doubts I had when solving these problems :
1. http://greprepclub.com/forum/25-of-1-4-of-x-3575.html
why (1/4)(400)(x) and not (1/4)(1/400)(x) ? (and the same in quantity B)
2. http://greprepclub.com/forum/mary-paid-for-a-book-was-equal-to-the-price-of-the-book-plus-1819.html
why 1.04x dollars and not 0.04x dollars?
Link for question 1: http:/
Link for question 1: http://greprepclub.com/forum/25-of-1-4-of-x-3575.html
Sorry, that was a typo. I've changed it to 1/400
Link for question 2: http://greprepclub.com/forum/mary-paid-for-a-book-was-equal-to-the-price...
If the price of the book is x dollars, then the TOTAL price (including the 4% sales tax) = 1.04x
Here's why:
If the (before tax) price = x, then...
0.04x = the 4% tax
So, the TOTAL price = x + 0.04x = 1.04x
At 7:48 I am trying to solve
You bet!
You bet!
We have (p/100)(80) = 120
One approach is to first eliminate the fraction by multiplying both sides by 100 (more on this approach here: https://www.greenlighttestprep.com/module/gre-algebra-and-equation-solvi...)
When we do this, we get: (p)(80) = 12,000
This is the same as 80p = 12,000
Now divide both sides by 80 to get: p = 150
Does that help?
Cheers,
Brent
Thank you!
Can you work out this problem
http://greprepclub.com/forum/geoff-used-630-to-buy-a-new-guitar-this-amount-was-15-perc-1899.html
You bet!
You bet!
Here's my solution: http://greprepclub.com/forum/geoff-used-630-to-buy-a-new-guitar-this-amo...
Cheers,
Brent
I solved this question as
0 < a < b
Quantity A: a% of 1/b
Quantity B: b% of 1/a
Solution:
qty A: a% *1/b
qty B : b% *1/a
qty A : a/100*1/b
qty B : b/100*1/a
qty A: .0a/b
qty B : .0b/a
qty A : smaller numerator/bigger denominator (as b>a given in shared info.)
qty B : Bigger numerator/smaller denominator (as b>a)
so qty B > qty A
Is this approach correct?
That solution is fine, but
That solution is fine, but converting a/100 to 0.0a is a little clunky.
For example, if a = 10%, we cannot say that a/100 = 0.010
So, here's what I'd do...
Given:
Quantity A: a% of 1/b
Quantity B: b% of 1/a
Rewrite as:
Quantity A: (a/100)(1/b)
Quantity B: (b/100)(1/a)
Simplify:
Quantity A: a/100b
Quantity B: b/100a
Multiply both sides by 100 to get:
Quantity A: a/b
Quantity B: b/a
Multiply both sides by b to get:
Quantity A: a
Quantity B: b²/a
Multiply both sides by a to get:
Quantity A: a²
Quantity B: b²
If 0 < a < b, then we can be certain that a² < b²
Answer: B
Cheers,
Brent
For that problem, aren't we
Quantity A: a/b
Quantity B: b/a
Given that 0 < a < b
You're absolutely right.
You're absolutely right.
If 0 < a < b, then we can be certain that b/a is greater than a/b.
I could have just as well stopped at that point.
Cheers,
Brent
1/16 of 10% of x
How did this become the below?
Quantity B: (1/16)(10)(x)
Did I accidentally writhe
Did I accidentally writhe that somewhere?
1/16 of 10% of x = (1/16)(10/100)(x)
7th question.
i understood now. All this while i thought 1/16 was 1/16% as quantity A had the first part in percentage (25%)
Good catch - thanks!
Good catch - thanks!
I've changed the 10 to 1/10 here: https://greprepclub.com/forum/25-of-1-4-of-x-3575.html#p7487
Cheers,
Brent
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