Beginning in 1997, high school seniors in State Q have been required to pass a comprehensive proficiency exam before they are allowed to graduate. The exam requirement was intended to ensure that a minimum level of academic quality will be achieved by the students in the state. In 1997, 20 percent of the seniors did not pass the exam and were, therefore, not allowed to graduate. In 1998, the number of seniors who passed the exam decreased by 10% from the previous year.

The argument above, if true, LEAST supports which of the following statement.


A. If the percentage of high school seniors who passed the exam increased from 1997 to 1998 , the number of high schools seniors decreased during that time period.

B. If the percentage of high school seniors who passed the exam decreased from 1997 to 1998 , the number of high schools seniors increased during that time period.

C. Unless the number of high school seniors was lower in 1998 than in 1997, the number of seniors who passed the exam in 1998 was lower than 80 percent.

D. If the number of high school seniors who did not pass the exam decreased by more than 10 percent from 1997 to 1998, the percentage of high school seniors who passed the exam in 1998 was greater than 80 percent.

E. If the percentage of high school seniors who passed the exam in 1998 was less than 70 percent, the number of high school seniors in 1997 was higher than the number in 1998.

This is a tough one but i'll share my 2 cents.

1997 - 80% pass/ 20% fail.
1998 - 72% pass/ 28% fail. (becasue the number of seniors who passed the exam decreased by 10% from 1997)

After reading options we can observe that only option (B) talks inline with the facts - If the percentage of high school seniors who passed the exam decreased from 1997 to 1998. Rest all talks weird/inconsistent number or percentage.

Let me know your thoughts. Cheers!
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The answer has to be E. No matter what initial number you pick for the number of students, the range mentioned in E is not possible, hence I figure it is the least possible, possibility being 0. How is the answer B?
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"Nowadays, people know the price of everything, and the value of nothing." Oscar Wilde

This question is tough.
Understand the assumption (hidden statement) is KEY

ANALYZE THE STIMULUS:

Fact: The argument says: In 1997, 20 percent of the seniors did not pass the exam and were, therefore, not allowed to graduate.
Fact: In 1998, the number of seniors who passed the exam decreased by 10% from the previous year.

What the argument implies?
It implies that from 1997 to 1998, the percentage of "NOT passed" the exam is still 20% (KEY), however, the number of seniors passed the exam decreased 10%. Therefore, the total number of high school seniors in 1998 was less than in 1997.

Example to back up
1997: total students: 100, passed: 80, not passed 20 (20%)
1998: total students: X, passed: 72 (less than 10% of 80) = 80% of X. KEY (the argument assumes the percentage of fails is still 20%)
Clearly, X must be fewer than 100.

How the argument can switch the object from "percentage of failed" (variable 1) to "the number of pass" (variable 2) without conflicts?
THE MAIN IDEA IS: The argument MUST FIX one variable to make the other variable be correct. If both variables are not fixed, the logic is out.

Now, we have an idea in mind “any answer that mention the number of students in 1997 is higher than that in 1998 is true”. Answer that mentions the total number of students in 1998 is higher than in 1997 will be out of logic ==> That's the option which will be LEAST supported by the stimulus.

ANALYZE EACH ANSWER:

A. If the percentage of high school seniors who passed the exam increased from 1997 to 1998 , the number of high schools seniors decreased during that time period.
Wrong. A mentions the number of high school seniors decreased from 1997 to 1998. This is true. So A will be supported by stimulus, hence A is wrong.

B. If the percentage of high school seniors who passed the exam decreased from 1997 to 1998 , the number of high schools seniors increased during that time period.
Correct. B mentions the case in which the number of high school seniors in 1998 is higher than that in 1997. Thus, B will be least supported by the stimulus. Hence, B is correct.

C. Unless the number of high school seniors was lower in 1998 than in 1997, the number of seniors who passed the exam in 1998 was lower than 80 percent.
Wrong. C implies that if the number of high school senior was equal or higher in 1998 than in 1997, the percentage of “passed” will be lower than 80%. It’s correct because the number of “passed” is fixed (10% less than in 1997), total number increases, percentage decreases. That’s the normal logic. C is also supported by the stimulus, hence C is wrong.

D. If the number of high school seniors who did not pass the exam decreased by more than 10 percent from 1997 to 1998, the percentage of high school seniors who passed the exam in 1998 was greater than 80 percent.
Wrong. Sure, it’s true. If the number of “NOT passed” decrease by more than 10% from 1997 to 1998, the percentage of “passed” increased. Thus, the number of high school who passed was greater. D is supported by the stimulus, D is wrong.

E. If the percentage of high school seniors who passed the exam in 1998 was less than 70 percent, the number of high school seniors in 1997 was higher than the number in 1998.
Wrong. VERY TEMPTING. E mentions the case in which the number of high school seniors in 1997 was higher than in 1998. It’s clearly be supported by the stimulus, hence E is wrong.

Hope it helps.
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Please +1 KUDO if my post helps. Thank you.

"Designing cars consumes you; it has a hold on your spirit which is incredibly powerful. It's not something you can do part time, you have do it with all your heart and soul or you're going to get it wrong."

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I think the answer is E. My explanation is in the attached picture.

Yes it is;
The key is to understand that this question requires you to breakdown and assimilate confusingly represented data.
In such cases putting down the logic / data points into manageable bits in your scratch pad/paper will help immensely.

Here's what the data says (I'm assuming that 1997's student strength is 100)
We know that
Pass = 80
Fail = 20

But in 1998 number of pass reduced by 10% of previous year: therefore total number of pass = 72
(note that they haven't told us what the total number of students is)

So let's account for all possibilities:
Student population of 1998 was 1. lower, 2. same, 3. more

Let me assign numbers
1. 80 then
Pass = 72
Fail = 8

2. 100
Pass = 72
Fail = 28

3. 200
Pass = 72
Fail = 128

Now let's look at the options:

A. If the percentage of high school seniors who passed the exam increased from 1997 to 1998 , the number of high schools seniors decreased during that time period. this refers to the second case and this statement is TRUE
B. If the percentage of high school seniors who passed the exam decreased from 1997 to 1998 , the number of high schools seniors increased during that time period. This is not necessary since if % of passing decreased - total could be equal OR more
C. Unless the number of high school seniors was lower in 1998 than in 1997, the number of seniors who passed the exam in 1998 was lower than 80 percent. Case 1 - TRUE
D. If the number of high school seniors who did not pass the exam decreased by more than 10 percent from 1997 to 1998, the percentage of high school seniors who passed the exam in 1998 was greater than 80 percent. This is TRUE - extrapolation of case 1
E. If the percentage of high school seniors who passed the exam in 1998 was less than 70 percent, the number of high school seniors in 1997 was higher than the number in 1998. This is TRUE - case 3

Hope that clarifies things!

Ajeeth Peo
Verbal Trainer - CrackVerbal
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hello.... with POE i come down to A and B and chose A ...
still not very clear but here's my try...

lets first dissect the plot
97- 80% pass 20% fail
98- 70% pass 30% fail
we need to see actual numbers will follow %ges only if total no remains the same....


C. Unless the number of high school seniors was lower in 1998 than in 1997, the number of seniors who passed the exam in 1998 was lower than 80 percent. yup getting support from our dissect

D. If the number of high school seniors who did not pass the exam decreased by more than 10 percent from 1997 to 1998, the percentage of high school seniors who passed the exam in 1998 was greater than 80 percent.totally supporting, we can see clearly if %fail decrease, then %Pass would increase...

E. If the percentage of high school seniors who passed the exam in 1998 was less than 70 percent, the number of high school seniors in 1997 was higher than the number in 1998 obviously if less ppl pass then no of studying will be greater

A. If the percentage of high school seniors who passed the exam increased from 1997 to 1998 , the number of high schools seniors decreased during that time period.yup getting support, but largely vague due to lack of specific info

B. If the percentage of high school seniors who passed the exam decreased from 1997 to 1998 , the number of high schools seniors increased during that time period.opposite to our dissect.

i was confused in A and B, but can see B clearly.... thank you guys
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correct if wrong, and a +1 wont hurt for like

Keep Faith in God Coz Every Question cannot be answered by Google

pkm9995109794 did a great job of breaking down each answer choice, but unfortunately he made a couple errors which led to not being able to answer the question. I do agree however, that this is a messed up question.

I'll go through it in the same way and use the same numbers so we can all see where the differences are.



Firstly, let's pick a few numbers to make our lives easy.
Let the total number of high school seniors in 1997 = 100
Then the number of high school seniors who passed in 1997 = 80 (given)
Then the number of high school seniors who passed in 1998 = 72 (given, decrease of 10%)
Let the total number of high school seniors in 1998 = x

It needs to be noted here that the question is tricky in that it refers to the percentage of students who passed, and also to a percentage decrease in the number of students who passed. These are two different things. One previous poster incorrectly assumed that this meant that the percentage of students who passed in 1998 was 70%. That is not true.

In fact we don't know what percentage of students passed in 1998. What we DO know is that the percentage of students who passed in 1997 = \(\frac{80}{100} = 80\%\) and that the percentage of students who passed in 1998 was \(\frac{72}{x}\). It will also be helpful to note that if x=90, then the percentage of students who passed in 1998 = \(\frac{72}{90} = 80\%\)
This will be used as a reference when we evaluate the answer choices.

Ok, the question:
The argument above, if true, LEAST supports which of the following statements.

A. If the percentage of high school seniors who passed the exam increased from 1997 to 1998 , the number of high schools seniors decreased during that time period.

This is saying that if \(\frac{72}{x}>80\%\), then x<100. Is this true based on the argument?

\(\frac{72}{x}>80\%\) means \(x<\frac{72}{0.8}\) which means \(x< 90\). So x<100, the statement is supported by the argument above. DISCARD


B. If the percentage of high school seniors who passed the exam decreased from 1997 to 1998 , the number of high schools seniors increased during that time period.

This is saying that if \(\frac{72}{x}<80\%\), then x>100. Is this true?
Using the same logic as in A. we can see that here x>90. That means it MIGHT be greater than 100, but is not definitive. POSSIBLE ANSWER.


C. Unless the number of high school seniors was lower in 1998 than in 1997, the number of seniors who passed the exam in 1998 was lower than 80 percent.

This is a tricky one. The word "unless" is basically the opposite of "if", or can be read as "if not". So "unless A happens, B happens" should be read as "If not A, then B". Applied to the statement, it can be read as "If the number of high school seniors was NOT lower in 1998 than in 1997, then the number of seniors who passed the exam in 1998 was lower than 80 percent.

Using our numbers, it looks like this: if \(x>100\), then \(\frac{72}{x}<80\%\)

We know if x=90, then 72/x = 80%, so if x>100, then 72/x must be < 80%. Statement is supported by the argument above. DISCARD


D. If the number of high school seniors who did not pass the exam decreased by more than 10 percent from 1997 to 1998, the percentage of high school seniors who passed the exam in 1998 was greater than 80 percent.

Number of students who did not pass the exam in 1997 = 20. If this number decreased by more than 10% then the number of students who did not pass the exam in 1998 < 18. (20-10%=18)

Therefore the number of students who did not pass the exam in 1998 = x-72 < 18. Meaning x<90
And the percentage of students who passed the exam in 1998 was greater that 80%. \(\frac{72}{x}>80\%\), and x<90. This is true, supported by the argument above. DISCARD


E. If the percentage of high school seniors who passed the exam in 1998 was less than 70 percent, the number of high school seniors in 1997 was higher than the number in 1998.

If \(\frac{72}{x}<70\%\), then 100>x

If \(x>\frac{72}{0.7}\), then x<100

If \(x>102\), then \(x<100\). Obviously false. This statement cannot be true based on the argument above.

But now we have a problem. Answer choice B is only partially supported by the argument, and answer choice E is contradicted by the argument. The way the question is phrased, "The argument above, if true, LEAST supports which of the following statements." could be interpreted as "Which of the following statement IS supported by the argument above, but supported the least". That way one could argue that B is the answer. But I don't think that is the correct interpretation of the question, and I'm not sure you can support less than by contradicting, which would suggest to me that the correct answer should be E, not B.

There could also possibly be a typo in answer choice E, swapping 1997 and 1998 in the second half of the statement. That would result in the statement being fully supported by the argument and the answer would then be a unanimous B.

Can anyone find an error in my analysis?

By the way, to do this in under 2 minutes would take some serious powers of time manipulation...

Cheers
_________________

Dave de Koos
GMAT aficionado

This question definitely needs fixing. As others have suggested, switching the years in E would easily make B the answer. If E is really the intended answer, then the question would need to clearly ask for an answer that "MUST BE FALSE." This is not something we'd usually see on the GMAT. In any case, when we're asked for an answer that is "least supported," there should really be four supported answers and one unsupported answer. The relative language "least" is just used to protect the test-writers in case we think of some slight exception or odd interpretation that might make two answers seem valid.
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Hi,

Responding to a PM...
Lets take a friendly number to check on choices..
Total seniors in 1997 = 100...
80 passed and 20 failed..

1998 - Total = T...
Passed = 90% of 80 = 72 and failed = F...

lets check the statements -
A. If the percentage of high school seniors who passed the exam increased from 1997 to 1998 , the number of high schools seniors decreased during that time period.
% in 1997 = 80%, and % in \(1998 = \frac{72}{T}\)....
\(\frac{72}{T}\) > 80%.... \(\frac{72}{T}> \frac{80}{100} ..... T < 72*\frac{100}{80}.... T<90\)...
so YES the number of high schools seniors decreased from 100 to LESS than 90 during that time period

B. If the percentage of high school seniors who passed the exam decreased from 1997 to 1998 , the number of high schools seniors increased during that time period.
% in 1997 = 80%, and % in 1998 = 72/T....
\(\frac{72}{T} < 80\)%....\(\frac{72}{T}< \frac{80}{100} ..... T > 72*\frac{100}{80}.... T>90...\)
so YES if the number of high schools seniors was 91 and
NO if it was 101 or 110 etc..
So this may not be TRUE everytime....

C. Unless the number of high school seniors was lower in 1998 than in 1997, the number of seniors who passed the exam in 1998 was lower than 80 percent.
let T< 100..... so 72/T <80/100..... T>90.....
so if T is between 90 and 100... ans is NO...% <80...
if T is <90... ans is YES > 80%
again Can be TRUE of FALSE..

D. If the number of high school seniors who did not pass the exam decreased by more than 10 percent from 1997 to 1998, the percentage of high school seniors who passed the exam in 1998 was greater than 80 percent.
% in 1997 = 80%, and % in \(1998 = \frac{72}{T}\)....
so # failed in 1997 = 20, and in 1998 #<18, say 17, so T = 72+17 = 89<90..
\(\frac{72}{(<90)}=x\) .... so x> 80%.
so YES the percentage of high school seniors who passed the exam in 1998 was greater than 80 percent.

E. If the percentage of high school seniors who passed the exam in 1998 was less than 70 percent, the number of high school seniors in 1997 was higher than the number in 1998.
so \(\frac{72}{T}<\frac{70}{100}..............T> 72*\frac{100}{70}.......... T> 102...\) so clearly ans is NO in every case..


Now we have B and C, which may be TRUE or FALSE, and E, which will always be FALSE..
so cleraly E is least supported...

OA given is B and many have found B to be correct..

But answer should be E, unless we mean LEAST supported means that the choice should be supported a bit but not completely..
And I do not think that should be the meaning
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1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html


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