Critical Reasoning

In 1984, network television commercials accounted for 80% of all network and non-network television advertising revenue. In 2004, that figure was 60%. During that same period, operating cost for the networks remained steady, and in 2004 every major network announced record setting profits.

The information above, if true, supports which of the following conclusions?

A) Between 1984 and 2004, the number of homes with access to non-network television channels increased by more than 20%.
B) Teenagers comprise a growing proportion of television viewers, and teenagers prefer to watch non-network television shows.
C) The amount of advertising revenue earned from non-network television commercials in 2004 was greater than the amount of revenue earned by network television commercials in 1984.
D) Between 1984 and 2004, advertising revenue earned from non-network television commercials grew at a faster rate than revenue earned from network television commercials.
E) Soon revenue from non-network television commercials will surpass revenue from network television commercials.


___________________________________________________
Correct Answer: D

I read the question first and classified this problem as a 'Draw Conclusion' type. Then I read the stimulus + answer choices and solved this problem using POE. Just to mention, I did get the correct answer in first attempt:
A) "the number of homes" --> Out of Scope
B) "Teenagers" -->Out of Scope
C) "amount" --> No information provided in stimulus; only % provided.
D) (Contender)
E) "will surpass" -->Future prediction = requires I make use of a real world assumption --> Out Of Scope.
Therefore, D is the correct answer.
Although I got the answer right but it was because other choices led me to the correct one through elimination (I had only one contender). But I could not understand the official explanation provided in the guide. I have seen similar problems that use dates (such as 1984, 2004 in this one) along with percentages (or numbers) and some of their solutions as posted on forums involve use of maths or deep reasoning. But I am not sure in a CR question if that is the most efficient strategy (Especially if the problem has lot of text as this one). So request you to kindly explain me the solution for this problem and also suggest me a general strategy to solve such problems that involve numbers (in percentage form or number form) so I do not panic when I see such questions on GMAT.

quiet confusing

imo C

I usually solve the statistical problem by picking number.*this approach does work for me.
For this case, let we jot down the premises.
1. In 1984, network television commercials accounted for 80% of all network and non-network television advertising revenue.
2. In 2004, that figure was 60%.
3. Operation cost for the networks remained steady. --> this info tells us that the cost wasn't the issue.
4. In 2004, every major network announced record setting profits. So, there is not unreported record.

Now, let we pick the smart numbers.

network revenue (in 1984) 80 (80%) (in 2004) 90 (60%)
non network (in 1984) 20 (20%) (in 2004) 60 (40%)
-------------------------------------------------------------
Total (in 1984) 100 (100%) (in 2004) 150 (100%)

From the figure above, there is no evidence to conclude that the number of homes with access to non-network television channels increased by more than 20% (eliminate A). We can quickly eliminate B as the teenagers proportion is out of scope.

C is not always true. it claimed that the amount of advertising revenue earned from "non-network television commercials" in 2004 was greater than the amount of revenue earned by "network television commercials" in 1984. My illustration shows that the revenue of network television in 1984 was greater than the revenue earned by non-network television (80>60).

D is the correct answer. The figure tells us that between 1984 and 2004, advertising revenue earned from non-network television commercials grew faster than the revenue from network television. (20 to 60 --> 200% increased while 80-90 --> only 12.5% increased)

We dont have enough evidence to accept E

Hope that helps.

Well... There is no strategy for this type of questions (which asks to choose best conclusion), unless you read answers. Because you can draw a lot of conclusions from given premises.

So, the best strategy is crossing out wrong answers.
A) Between 1984 and 2004, the number of homes with access to non-network television channels increased by more than 20% (could be, but you not enough information in order to draw this conclusion)

B) Teenagers comprise a growing proportion of television viewers, and teenagers prefer to watch non-network television shows. (Information is not enough to draw this conclusion)

C) The amount of advertising revenue earned from non-network television commercials in 2004 was greater than the amount of revenue earned by network television commercials in 1984. (Wrong. Let's say that all network and non-network television advertising revenue is X. Then in 1984, network TV commercials' revenue was 0.8*X. Then non-network tv's revenue is 0.2*X. In 2004, network TV commercials' revenue was 0.6*Y. Then non-network tv's revenue was 0.4*Y, which means still less than network tv commercials' revenue)

D) Between 1984 and 2004, advertising revenue earned from non-network television commercials grew at a faster rate than revenue earned from network television commercials. (Right. Because in 2004 it grew from 0.2*X to 0.4*X, which means in percent it grew faster)

E) Soon revenue from non-network television commercials will surpass revenue from network television commercials. (Not enough information)

Although I got the answer right but it was because other choices led me to the correct one through elimination (I had only one contender). But I could not understand the official explanation provided in the guide. I have seen similar problems that use dates (such as 1984, 2004 in this one) along with percentages (or numbers) and some of their solutions as posted on forums involve use of maths or deep reasoning. But I am not sure in a CR question if that is the most efficient strategy (Especially if the problem has lot of text as this one). So request you to kindly explain me the solution for this problem and also suggest me a general strategy to solve such problems that involve numbers (in percentage form or number form) so I do not panic when I see such questions on GMAT.

Some math over here could seem a bit long, but in mind it will be quick and I think approximiate calculations in mind is necessary strategy.[/quote]

Thanks folks for your prompt help! Both the smart number and algebra strategies are great.

But what would be the recommended approach: Do I get to this level of maths as I read the stimulus or only if I have more than one contender (after POE)?

I am concerned because when drawing a conclusion our task is to determine what 'MUST BE TRUE' logically but if we involve maths in our reasoning then our task suddenly becomes proving 'WHAT IS TRUE' mathematically. Although latter works but I was wondering if there is an alternate strategy.
I am a big fan of Testluv and Stacey Koprince and wonder what approach they recommend for similar questions!:)

prsnt11 wrote:In 1984, network television commercials accounted for 80% of all network and non-network television advertising revenue. In 2004, that figure was 60%. During that same period, operating cost for the networks remained steady, and in 2004 every major network announced record setting profits.

The information above, if true, supports which of the following conclusions?

A) Between 1984 and 2004, the number of homes with access to non-network television channels increased by more than 20%.
B) Teenagers comprise a growing proportion of television viewers, and teenagers prefer to watch non-network television shows.
C) The amount of advertising revenue earned from non-network television commercials in 2004 was greater than the amount of revenue earned by network television commercials in 1984.
D) Between 1984 and 2004, advertising revenue earned from non-network television commercials grew at a faster rate than revenue earned from network television commercials.
E) Soon revenue from non-network television commercials will surpass revenue from network television commercials.


___________________________________________________
Correct Answer: D

I read the question first and classified this problem as a 'Draw Conclusion' type. Then I read the stimulus + answer choices and solved this problem using POE. Just to mention, I did get the correct answer in first attempt:
A) "the number of homes" --> Out of Scope
B) "Teenagers" -->Out of Scope
C) "amount" --> No information provided in stimulus; only % provided.
D) (Contender)
E) "will surpass" -->Future prediction = requires I make use of a real world assumption --> Out Of Scope.
Therefore, D is the correct answer.
Although I got the answer right but it was because other choices led me to the correct one through elimination (I had only one contender). But I could not understand the official explanation provided in the guide. I have seen similar problems that use dates (such as 1984, 2004 in this one) along with percentages (or numbers) and some of their solutions as posted on forums involve use of maths or deep reasoning. But I am not sure in a CR question if that is the most efficient strategy (Especially if the problem has lot of text as this one). So request you to kindly explain me the solution for this problem and also suggest me a general strategy to solve such problems that involve numbers (in percentage form or number form) so I do not panic when I see such questions on GMAT.

is that the official answer you got from the book you reaD?

Yes diebeatsthegmat. D is the correct answer as per the book.

prsnt11 wrote:Yes diebeatsthegmat. D is the correct answer as per the book.

If u have noted in option D, "rate" is used. So it implies Percent change of 2 entities.

P1 : percent change from revenue earned from network television commercials.

{(60 -80) /80 } * 100


= - 25 %

P2: percent change from non-network television commercials

{(40-20)/ 20} * 100

= 100%

So now its clear that P2 is greater than P1.

SO D is clear!! hope this helps!

@TestLuv dada!! Plz pitch in!!