Critical Reasoning

How to canswer such questions in less than 2 mins?

Some official Web sites of regionally accredited colleges have received the highest possible rating from the Federal Department of Education. However, all official Web sites of nationally accredited colleges have received the highest possible rating from the same department.

Which of the following, if added to the statements above, would provide most support for the conclusion that all Web sites administered by individuals holding advanced degrees in educational technology have received the highest possible rating from the Federal Department of Education?

[A] Only official Web sites of nationally accredited colleges are administered by individuals holding advanced degrees in educational technology.

All official Web sites of nationally accredited colleges are administered by individuals holding advanced degrees in educational technology.

[C] Only Web sites that have not received the highest possible rating from the Federal Department of Education are administered by individuals not holding advanced degrees in educational technology.

[D] All official Web sites of nationally accredited colleges are administered by individuals holding advanced degrees in educational technology.

[E] No Web site administered by individuals holding advanced degrees in educational technology is an official Web site of a regionally accredited college.

https://www.beatthegmat.com/web-sites-t23923.html

Good explanation by dmateer.

cramya wrote:https://www.beatthegmat.com/web-sites-t23923.html

Good explanation by dmateer.

Cramya, could you please throw some light on why (C) is wrong? I have visited the link and am still not sure why (C) is not the answer.

Premise 1: Some websites of regionally accredited colleges have received the highest possible rating
Premise 2: All websites of nationally accredited colleges have received the highest possible rating
conclusion: ALL Web sites administered by individuals holding advanced degrees in educational technology have received the highest possible rating

(A) is undoubtedly a correct answer.

But (C) says, "Only Web sites that have not received the highest possible rating from the Federal Department of Education are administered by individuals not holding advanced degrees in educational technology. " In other words, all websites that have received the highest possible rating from the Federal Department of Education are administered by individuals holding advanced degrees in educational technology. how is it different from the conclusion? Please help me understand, if I am overlooking some point.

To be honest, I have serious doubt about this question. I can not imagine even the worst GMAT question having repeated answer choice. Still, I would like to understand this problem, for the sake of clarity of reasoning.

Hi Uri
To ans your question why is "C" wrong
take a step back read this "https://www.math.jmu.edu/~taal/235_2000post/235logic.pdf"

you will be convinced that "If A, then B" from this you can conclude only "If not B then not A" and nothing else.
all other options like "If not A, then not B" are wrong

HTH

I would choose C. But i am not sure of my answer