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In a certain medical survey, 45 percent of the people surveyed had the

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carcass
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In a certain medical survey, 45 percent of the people surveyed had the [#permalink] New post  25 Jul 2017, 11:28
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In a certain medical survey, 45 percent of the people surveyed had the type A antigen in their blood and 3 percent had both the type A antigen and the type B antigen. Which of the following is closest to the percent of those with the type A antigen who also had the type B antigen?

A. 1.35%

B. 6.67%

C. 13.50%

D. 15.00%

E. 42.00%
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In a certain medical survey, 45 percent of the people surveyed had the [#permalink] New post  19 Aug 2017, 15:51
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Quote:
carcass wrote:

In a certain medical survey, 45 percent of the people surveyed had the type A antigen in their blood and 3 percent had both the type A antigen and the type B antigen. Which of the following is closest to the percent of those with the type A antigen who also had the type B antigen?

A. 1.35%

B. 6.67%

C. 13.50%

D. 15.00%

E. 42.00%

dyee630k wrote:
Why can't the trick .45 * .03 be used here?

dyee630k - The key phrasing is not easy to translate. :-)

If you had a Venn diagram, with a circle for A only, a circle for B only, and overlap of A and B, the question asks what percentage of circle "A only" the overlap "A and B" is.

Let's say 100 people, so
45 = A only
3 = A and B

"the percent of those with the type A antigen [45] . . . who also had the type B antigen? [3]" IS WHAT?

Or, "What percent of 45 is 3?"

Or, "3 is what percent of 45?"

The percentage is the variable: (\(\frac{x}{100}\))(45) = 3

\(\frac{x}{100}\) = \(\frac{3}{45}\)

45x = 300
x = 6.67

Hope it helps.
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Re: In a certain medical survey, 45 percent of the people surveyed had the [#permalink] New post  25 Jul 2017, 23:21
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carcass wrote:
In a certain medical survey, 45 percent of the people surveyed had the type A antigen in their blood and 3 percent had both the type A antigen and the type B antigen. Which of the following is closest to the percent of those with the type A antigen who also had the type B antigen?

A. 1.35%

B. 6.67%

C. 13.50%

D. 15.00%

E. 42.00%


Type A = 45
Type A and B = 3.

The percent of those with the type A antigen who also had the type B antigen \(= \frac{(Type \ A \ and \ B)}{(Type \ A)}*100 = \frac{3}{45}*100 = \frac{20}{3} \approx 6.67%\).

Answer: B.
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Re: In a certain medical survey, 45 percent of the people surveyed had the [#permalink] New post  26 Jul 2017, 16:22
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carcass wrote:
In a certain medical survey, 45 percent of the people surveyed had the type A antigen in their blood and 3 percent had both the type A antigen and the type B antigen. Which of the following is closest to the percent of those with the type A antigen who also had the type B antigen?

A. 1.35%

B. 6.67%

C. 13.50%

D. 15.00%

E. 42.00%


We can let the total people = 100. Since 45 percent of them had the type A antigen, we know that 45 of the people had the type A antigen. We also know that 3 percent had both the A and B antigen in their blood. Thus, of the 45 people who had the type A antigen, 3 of them also had the type B antigen. Thus, the percentage is 3/45 x 100% = 6.67%.

Answer: B
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Re: In a certain medical survey, 45 percent of the people surveyed had the [#permalink] New post  19 Aug 2017, 07:49
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Why can't the trick .45 * .03 be used here?
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Re: In a certain medical survey, 45 percent of the people surveyed had the [#permalink] New post  10 May 2018, 06:02
Bunuel wrote:
carcass wrote:
In a certain medical survey, 45 percent of the people surveyed had the type A antigen in their blood and 3 percent had both the type A antigen and the type B antigen. Which of the following is closest to the percent of those with the type A antigen who also had the type B antigen?

A. 1.35%

B. 6.67%

C. 13.50%

D. 15.00%

E. 42.00%


Type A = 45
Type A and B = 3.

The percent of those with the type A antigen who also had the type B antigen \(= \frac{(Type \ A \ and \ B)}{(Type \ A)}*100 = \frac{3}{45}*100 = \frac{20}{3} \approx 6.67%\).

Answer: B.


Bunuel, Why are we dividing 3 by 45 to find answer? Is the question not asking us to find 3% of 45% and then that represents how much of total as a percent?
Moreover, I am confused whether the question says 3% of 45% or 3% of total?

Do not mean to trouble you. :angel:
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Re: In a certain medical survey, 45 percent of the people surveyed had the [#permalink] New post  10 May 2018, 22:58
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siddreal wrote:
Bunuel wrote:
carcass wrote:
In a certain medical survey, 45 percent of the people surveyed had the type A antigen in their blood and 3 percent had both the type A antigen and the type B antigen. Which of the following is closest to the percent of those with the type A antigen who also had the type B antigen?

A. 1.35%

B. 6.67%

C. 13.50%

D. 15.00%

E. 42.00%


Type A = 45
Type A and B = 3.

The percent of those with the type A antigen who also had the type B antigen \(= \frac{(Type \ A \ and \ B)}{(Type \ A)}*100 = \frac{3}{45}*100 = \frac{20}{3} \approx 6.67%\).

Answer: B.


Bunuel, Why are we dividing 3 by 45 to find answer? Is the question not asking us to find 3% of 45% and then that represents how much of total as a percent?
Moreover, I am confused whether the question says 3% of 45% or 3% of total?

Do not mean to trouble you. :angel:


Say there are 100 people.

45 out of 100 had the type A antigen;
3 out of 100 had both the type A antigen and the type B antigen.

The question asks: what percent of those who had the type A antigen (45) also had the type B antigen (3)? So, what percent of those who had the type A antigen (45) had both (3). Basically we should find what percent is 3 of 45: \(\frac{3}{45}*100\).
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Re: In a certain medical survey, 45 percent of the people surveyed had the [#permalink] New post  12 Nov 2019, 12:22
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I couldn't solve it because I failed to grasp the question.
I just couldn't think of what on earth "the percent of those with the type A antigen who also had the type B antigen" means. Poor me!
If it read "what percent of those with the type A antigen is those with both type A and B antigen, it would have been a better prospect for me.

Maybe that's the GMAT's way.
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Re: In a certain medical survey, 45 percent of the people surveyed had the [#permalink] New post  06 Jul 2020, 05:17
ScottTargetTestPrep wrote:
carcass wrote:
In a certain medical survey, 45 percent of the people surveyed had the type A antigen in their blood and 3 percent had both the type A antigen and the type B antigen. Which of the following is closest to the percent of those with the type A antigen who also had the type B antigen?

A. 1.35%

B. 6.67%

C. 13.50%

D. 15.00%

E. 42.00%


We can let the total people = 100. Since 45 percent of them had the type A antigen, we know that 45 of the people had the type A antigen. We also know that 3 percent had both the A and B antigen in their blood. Thus, of the 45 people who had the type A antigen, 3 of them also had the type B antigen. Thus, the percentage is 3/45 x 100% = 6.67%.

Answer: B


Why it's over 45? Shouldn't it be over the total of 100?
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Re: In a certain medical survey, 45 percent of the people surveyed had the [#permalink] New post  09 Jul 2020, 13:25
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lakshya14 wrote:
ScottTargetTestPrep wrote:
carcass wrote:
In a certain medical survey, 45 percent of the people surveyed had the type A antigen in their blood and 3 percent had both the type A antigen and the type B antigen. Which of the following is closest to the percent of those with the type A antigen who also had the type B antigen?

A. 1.35%

B. 6.67%

C. 13.50%

D. 15.00%

E. 42.00%


We can let the total people = 100. Since 45 percent of them had the type A antigen, we know that 45 of the people had the type A antigen. We also know that 3 percent had both the A and B antigen in their blood. Thus, of the 45 people who had the type A antigen, 3 of them also had the type B antigen. Thus, the percentage is 3/45 x 100% = 6.67%.

Answer: B


Why it's over 45? Shouldn't it be over the total of 100?


We are looking for "percent of A" who also had B, so we have 3/45 x 100.
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Re: In a certain medical survey, 45 percent of the people surveyed had the [#permalink] New post  24 Aug 2020, 06:51
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Type A antigen: 45%

Type A and B: 3%

Percent of those with the type A antigen who also had the type B antigen (Transforming into the equation)

=> Percent of (Type A) = also had the type B

=> Let it be x% of TYPE A who had both A and B.

=> \(\frac{x }{ 100}\) * 45 = 3

=> x = \(\frac{300}{45}\)

=> x = 6.67%

Answer B
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Re: In a certain medical survey, 45 percent of the people surveyed had the [#permalink] New post  01 Aug 2021, 15:57
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If anyone actually communicated this way in real life, they should be fired. This is the most poorly written question I have ever come across while studying for the GMAT - simply poor use of the English language. It's as if the writer said, "I'm tired of writing. I'm just going to create an equation, then word it in a manner that is convoluted and can be broadly interpreted, and let others justify how I communicated it."
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In a certain medical survey, 45 percent of the people surveyed had the [#permalink] New post  Updated on: 27 Aug 2021, 17:59
Hi avigutman - Two followups when reviewing the question : Which is closest to the percent of those with the type A antigen who also had the type B antigen?

Isn't there a partition missing ?

If i want to ask about 3 % of A specifically -- looking at other official overlapping set problems here and here -- The verbiage with transposed data for 3 % of A specifically should be

Quote:
  • what percent of those with Antigen A have antigen A and antigen B
  • what percent of those with Antigen A have BOTH antigens
  • what is the probability that the person with Antigen A will be the one who has both Antigen A and Antigen B

Partition seperating denominator and numerator in yellow in each case


There is a clear partition seperating the denominator (which comes first) + partition + numerator

Is "HAD" perhaps the partition ?

Originally posted by jabhatta2 on 25 Aug 2021, 12:14.
Last edited by jabhatta2 on 27 Aug 2021, 17:59, edited 4 times in total.
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In a certain medical survey, 45 percent of the people surveyed had the [#permalink] New post  27 Aug 2021, 17:55
Hi avigutman - q2

If "HAD" is perhaps the partition , that takes care of the denominator but the numerator still can have 2 interpretations intereprations
    [interpretation # 1] (A and B) / A
    or
    [interpretation # 2] (A or B) / A

Why do you think interpretation # 2 is not an accurate way of thinking about the original sentence.
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Re: In a certain medical survey, 45 percent of the people surveyed had the [#permalink] New post  28 Aug 2021, 07:19
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jabhatta2 wrote:
Hi avigutman - q2

If "HAD" is perhaps the partition , that takes care of the denominator but the numerator still can have 2 interpretations intereprations
    [interpretation # 1] (A and B) / A
    or
    [interpretation # 2] (A or B) / A

Why do you think interpretation # 2 is not an accurate way of thinking about the original sentence.



Quote:
Which of the following is closest to the percent of those with the type A antigen who also had the type B antigen?

Every fraction or percent or rate or ratio has a top and a bottom (a numerator and a denominator).
I color coded the parts of the text in the hopes that this will remove all doubts.
I invite others to color code the parts of the text in ways that would lead to different meanings - I cannot think of any other way in which to color code them.
jabhatta2 interpretation # 2 is not accurate because of the word also in the original text. To your first question: the partition is who.
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Re: In a certain medical survey, 45 percent of the people surveyed had the [#permalink] New post  03 Jan 2024, 12:42
carcass wrote:
In a certain medical survey, 45 percent of the people surveyed had the type A antigen in their blood and 3 percent had both the type A antigen and the type B antigen. Which of the following is closest to the percent of those with the type A antigen who also had the type B antigen?

A. 1.35%

B. 6.67%

C. 13.50%

D. 15.00%

E. 42.00%


For people struggling with calculation, let me help you.

you do not need ot find the excat number to get the answer right.

here we go: rephrase the question (which for me is the hardest step of the question).
"3 is what percent of 45"

10% of 45 is 4.5; 5% of 45 is 2.25.

therefore, 3 is between 10% and 5% +> the only answer possible is 6.67%
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Re: In a certain medical survey, 45 percent of the people surveyed had the [#permalink]
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