#12 - Shaw: Regulatory limits on pollution emissions from power plants should be

[Administrator]

Complete Question Explanation

Method-AP. The correct answer choice is (D).

Answer choice (A):

Answer choice (B):

Answer choice (C):

Answer choice (D): This is the correct answer choice.

Answer choice (E):

[ChicaRosa]

I had a hard time understanding the stimulus in trying to compare the analogy that the question was asking. How is D) "emits no pollutants at all" comparable to time a vehicle spends at a stoplight?

Thanks!

[David Boyle]

I had a hard time understanding the stimulus in trying to compare the analogy that the question was asking. How is D) "emits no pollutants at all" comparable to time a vehicle spends at a stoplight?

Thanks!

Hello ChicaRosa,

A vehicle at a stoplight isn't moving; a factory emitting no pollutants at all is doing nothing, if we're only considering pollutants. So, a stopped car is like a stopped factory.

Hope this helps,
David

[mN2mmvf]

I'm confused about this question as well. When vehicles are stopped at a stoplight (or in traffic, to use the other comparison in the stimulus) the engines of the vehicles are still on, idling, emitting a low level of pollutants. Likewise, operating power plants are presumably never entirely switched off, but rather idle during non-peak times and emit only low levels of pollutants.

How could (D) be the right answer, then? If the question had asked about a car that was parked, I would understand the rationale for (D). But a stoplight sounds a lot more like (C) to me.

[Adam Tyson]

Be careful about what is being compared here, mN2mmvf! The author is not comparing the pollution of a stopped car to the pollution of an idle factor. Rather, he is comparing the speed of a stopped car to the pollution of an idle factory! The comparison was about taking into account the time that a car is not moving and averaging that in when considering whether it has violated a speed limit, which is (according to Levin) like taking into account the time that a factory is not polluting and averaging that in when considering maximum pollution limits.

That's an easy one to get tripped up by, and answer C is there waiting for everyone that makes that same mistake.

I'd also caution you to be careful about making assumptions not supported by the stimulus. You presumed that an idle factory is still emitting low levels of pollutants, but the stimulus never says that, and it would be just as reasonable to presume that an idle factory is truly idle, shut down, emitting nothing at all. Since we cannot know about that from the stimulus, we should avoid bringing that idea into our analysis.

Take another look and see if the comparison of stopped to not-polluting makes more sense to you now. Keep up the good work!

[mN2mmvf]

Thanks - very helpful! The speed vs. emissions distinction makes sense.

[lavalsat]

To correctly answer this question- we need to assume that vehicles during "time.. at stoplights" equates to the vehicles not moving. I got the question right, but I do not feel like that is a fair assumption to make. I would say it is common knowledge that the majority of vehicles move somewhat during their time spent "at stoplights". This seems like the assumption LSAC needs people to make is too much/too traditional.

[Poonam Agrawal]

Hi lavalsat,

I think that's definitely an interesting point. We have to keep in mind, though, that people are supposed to come to a complete stop at stoplights. Sometimes cars move a couple of inches while stopped, but overall, most cars do completely stop moving when at a red light.

The stimulus does try to make a distinction between "low" movement and "no" movement by mentioning both traffic and stoplights. Traffic would be analogous to pollution at a low level, and stoplights would therefore be analogous to no pollutants at all.

Thanks for bringing up an interesting point! Good luck with your studying.