PTFeb97.S1.Q20 - explosion of interest in opera

ChiChi55

I have a hard time understanding why B is the right answer? Also, could someone explain why D is wrong?

jmarmaduke96

Hi @ChelseaT!

I'll do my best to try to explain this one. The argument is a little confusing because it ends with its premise, so properly worded the argument would say "Of the 70 or so professional opera companies currently active in North America, 45 were founded over the course of the last 30 years. Therefore, in North America there has been an explosion of public interest in, and enjoyment of, opera over the last three decades."

Answer choice B states that "There were fewer than 45 professional opera companies that had been active 30 years ago and that ceased operation in the last 30 years." I believe that the easiest way to see why this is a necessary assumption is to negate it, put it back into the argument, and see how the argument fairs. There are two ways to negate it, with either the logical opposite or the polar opposite. The polar opposite is more apparent, so we will look at that first. If we reword answer choice B to say "There were MORE than 45 (lets say 60?) professional opera companies that had been active 30 years ago and that ceased operation in the last 30 years." that is the polar opposite. Now lets plug that into the argument

"Of the 70 or so professional opera companies currently active in North America, 45 were founded over the course of the last 30 years. However, there were 60 professional opera companies that had been active 30 years ago and that ceased operation in the last 30 years. Therefore, in North America there has been an explosion of public interest in, and enjoyment of, opera over the last three decades."

Do you see how the argument is contradicting itself now? it has fallen apart, it is trying to convince us that interest in opera has exploded because 45 opera companies were founded in this timeframe, but it also tells us that 60 companies have closed. So it seems that the conclusion does not follow at all and it is more likely that public interest has gone down. You can do the same thing with the logical negation, and say that "EXACTLY 45" opera companies have closed down. You will see the same error, the argument directly undermines the evidence that it uses in support of its conclusion when the answer choice is negated. Therefore, answer choice B is a necessary assumption to allow the conclusion to follow.

As far as answer choice D, that says that "The size of the average audience at performances by professional opera companies has increased over the past three decades." Lets apply the same trick, and negate the answer choice so that instead of the audience size increasing, it has stayed the same, and plug it into the argument.

"Of the 70 or so professional opera companies currently active in North America, 45 were founded over the course of the last 30 years. Therefore, even though the size of the average audience at a professional opera performance has stayed the same, the number of additional opera companies shows that in North America there has been an explosion of public interest in, and enjoyment of, opera over the last three decades."

Does that make sense? Because the number of companies has expanded, it does not mean the the average size of the audience has to have risen as well in order for the conclusion to follow. I hope that helps, let me know if I can clarify anything!

ChiChi55

@jmarmaduke96
Thank you SO much! That helps a ton. I guess I was thinking that audience size means public interest but it makes sense now why B is the correct answer, especially since it relates more to the evidence being used in the stimulus.