In the 1980's, astronomer Bohdan Paczynski proposed a way of determini

for many short passages in og, gmatprep, the first question about the main idea is hard while the second or third question about a detail in the passage is easy. this passage is an example of this point.

for 2 and 3, the answer is B and D clearly.

for the first, which I feel hard, the answer is C.

Hi adymehta29,
Below is my reasoning to cancel D.
D)temporarily increase the apparent brightness of a star in the Large Magellanic Cloud by increasing the gravity of the star.
"The gravity of a MACHO that had so drifted, astronomers agree, would cause the star's light rays, which would otherwise diverge, to bend together so that, as observed from Earth, the star would temporarily appear to brighten, a process known as microlensing."

As per the argument, MACHO doesn't increase the gravity to achieve mentioned effect. It's the "drifted gravity " that does it.

Hope this answers your query.
Regards.

Thanks a lot . I support your strategy in fully comprehending the passage first then answering the questions. Sometimes if it is a scientific passage I prefer not to spend so much time understanding the passage fully but just to get a general understanding of what every paragraph speaks about.



quote="deepakpatter"]
Well that depends on the length of the passage
Normally for a long passage you should take max to max 5 mins reading so you get the data in your mind. After this the questions are piece of cake.
This is my strategy. Some people just vertical scan the passage in less than minute but i don't prefer that. My strategy works best for me.
Try if it helps.
Once you grasp the content believe me you'll find the answers to the questions so easily within seconds.
KEEP IN MIND..! Avoid reading again and again is the key to rc's. Take time but do it once.
Best if luck..!![/quote]

It helped . (y)
thnx a lot
My speed. Is slow with. Rc's
Suggest me something. And am getting 050 percent. Of the answer s wrong

Took 5 mins 10 seconds , including 2 mins 10 seconds to read
-The author describes a theory put forth by an astronomer
- The author the points out certain astronomers' concerns regarding the theory
- The author then addresses those concerns

1.
Answer E

2. "The gravity of a MACHO that had so drifted, astronomers agree, would cause the star's light rays, which would otherwise diverge, to bend together so that, as observed from Earth, the star would temporarily appear to brighten"
Answer B

3.
"all of a star's colors are equally affected by microlensing. Thus, if a MACHO magnifies a star's red light tenfold, it will do the same to the star's blue light and yellow light."
Answer D

In the 1980's, astronomer Bohdan Paczynski proposed a way of determining whether the enormous dark halo constituting the outermost part of the Milky Way galaxy is composed of MACHO's (massive compact halo objects), which are astronomical objects too dim to be visible. Paczynski reasoned that if MACHO's make up this halo, a MACHO would occasionally drift in front of a star in the Large Magellanic Cloud, a bright galaxy near the Milky Way. The gravity of a MACHO that had so drifted, astronomers agree, would cause the star's light rays, which would otherwise diverge, to bend together so that, as observed from Earth, the star would temporarily appear to brighten, a process known as microlensing. Because many individual stars are of intrinsically variable brightness, some astronomers have contended that the brightening of intrinsically variable stars can be mistaken for microlensing. However, whereas the different colors of light emitted by an intrinsically variable star are affected differently when the star brightens, all of a star's colors are equally affected by microlensing. Thus, if a MACHO magnifies a star's red light tenfold, it will do the same to the star's blue light and yellow light. Moreover, it is highly unlikely that a star in the Large Magellanic Cloud will undergo microlensing more than once, because the chance that a second MACHO would pass in front of exactly the same star is minuscule.

2. According to the passage, Paczynski's theory presumes that if MACHO's constituted the Milky Way's dark halo, occasionally a MACHO would
A. drift so as to lie in a direct line between two stars in the outer Milky Way
B. affect the light rays of a star in the Large Magellanic Cloud with the result that the star would seem for a time to brighten
C. become obscured as a result of the microlensing of a star in the Large Magellanic Cloud
D. temporarily increase the apparent brightness of a star in the Large Magellanic Cloud by increasing the gravity of the star
E. magnify each color in the spectrum of a star in the Large Magellanic Cloud by a different amount

Hi sayantanc2k / Experts,

Can somebody explain In Question 2, why not option A is correct? In the passage it says "Paczynski reasoned that if MACHO's make up this halo, a MACHO would occasionally drift in front of a star in the Large Magellanic Cloud, a bright galaxy near the Milky Way."

Hi,
This question is actually a 'Specific' type of RC question that requires paraphrase of something directly from the passage ( no assumption) .The statment in option A can not be justified by passage. In passage line related to this mentioned is 'Paczynski reasoned that if MACHO's make up this halo, a MACHO would occasionally drift in front of a star in the Large Magellanic Cloud, a bright galaxy near the Milky Way' . If you read carefully , nowhere star's position is mentioned to be in a line between two stars. We have to find a answer which can be inferred from the passage .

in question 1, answer choice b and e are close. choice b is wrong because of "data". there is no data here. choice e is problematic .not researcher but astronomer propose. this can be a mistake from gmac

reading gmat passage dose not require new words. in other words, if you get toefl 80 ibt, you have enough vocabulary for reading passage gmat.

gmat reading require you to read complex sentences with complex ideas. practice this skill. vocabulary is not hard but sentences are long and complex. the ideas in the sentences are hard to understand.
at first, we practice reading text with easy ideas, and realizing grammar things. latter, we practice reading the text and realizing grammar and understanding hard ideas in the text. the second level is gmat level. no problem of new words is here. dont try to learn new words.

for advanced learners, the difficulty is not limited vocabulary but the world of ideas. we need to be good at reading and realizing grammar in the easy text before to be good at reading and realizing complex ideas in hard text.

Process map:
if MACHO exist, the star will brighten (microlensing).
variable brightness or ml?
can identify difference - 1) ml equally affect all colors while the variable feature doesn't 2) frequency of ml is low - implying variable brightness feature occurs more often

1. The passage is primarily concerned with

A. outlining reasons why a particular theory is no longer credited by some astronomers the theory is argued by astronomers but isn't "no longer credited"
B. presenting data collected by a researcher in response to some astronomers' criticism of a particular line of reasoning
C. explaining why a researcher proposed a particular theory and illustrating how influential that theory has been it didn't explain why and didn't illustrate the importance neither. In order to comment on how influence it is, author will need to evaluate its application, but in this passage he/she didn't
D. showing how a researcher's theory has been used to settle a dispute between the researcher and some astronomers the theory is not used to settle a disputer - rather that theory is distributed, and then astronomers have some doubts which are clarified afterwards
E. describing a line of reasoning put forth by a researcher and addressing a contention concerning that line of reasoning correct answer, the passage begins with a reasoning, cite astronomer's doubt and then provide reason to address their concern


2. According to the passage, Paczynski's theory presumes that if MACHO's constituted the Milky Way's dark halo, occasionally a MACHO would

A. drift so as to lie in a direct line between two stars in the outer Milky Way "lie in direct line" is not mentioned
B. affect the light rays of a star in the Large Magellanic Cloud with the result that the star would seem for a time to brighten this coincides with "temporarily appear to brighten" and "cause the star's light rays to bend together..."
C. become obscured as a result of the microlensing of a star in the Large Magellanic Cloud "obscured" is the opposite description of what occurred in the passage
D. temporarily increase the apparent brightness of a star in the Large Magellanic Cloud by increasing the gravity of the star mix-up answer - the first half looks right while the 2nd is wrong, gravity change of the star is not mentioned
E. magnify each color in the spectrum of a star in the Large Magellanic Cloud by a different amount opposite to what the passage described - all colors are affects equally


3. It can be inferred from the passage that which of the following would constitute the strongest evidence of the microlensing of a star in the Large Magellanic Cloud?

A. The brightness of such a star is observed to vary at irregular intervals. "irregular intervals" is wrong - microlensing barely occurs for the 2nd time given "the chance that a second MACHO would pass in front of exactly the same star is minuscule"
B. The brightening of such a star is observed to be of shorter duration than the brightening of neighboring stars. the frequency comparison is not mentioned, all we know is the brightening is temporary
C. The red light of such a star is observed to be brighter than its yellow light and its blue light. all colors are affected equally, so this cannot be right
D. The red light, yellow light, and blue light of such a star are observed to be magnified temporarily by the same factor. correct answer
E. The red light of such a star is observed to have increased tenfold. mix-up answer, "tenfold" is mentioned" but the necessary condition for microlensing - which should be all colors being enhanced equally

For the question 1 - "astronomers" are researchers. If we don't understand that, question 1 will sound alien as the author hasn't used the word researchers in the passage. Astronomers are researchers, but not all researchers are astronomers. The choice of words could have been better, but that's out of our control.