Q2 - A certain type of insect trap uses

[melmoththewanderer88]

I have a question concerning this question...

I chose 'B' here and I still cannot find grounds to exclude it as incorrect.

My understanding of the argument is that several traps reduces the number of beetles in the garden, but one trap will tend to increase the number of beetles in the garden.

If as B says, several traps catch them better than 1 would, then that should explain the paradox, no? What am I missing here?

[sumukh09]

Your understanding of the argument is correct but you're missing one key point in your analysis of the answer choices; that point being: why do the number of rose beetles in the garden increase if only one trap is installed. All B is saying is that one trap is less effective than multiple traps because the rose beetles will eventually get caught in one of the traps. But what B doesn't help explain is why the number of rose beetles would increase.

D hits both sides of the paradox. If the presence of any traps attracts "more" rose beetles than we can assume that one trap will attract more than several since there's only one trap and rose beetles may evade this trap and ultimately not get caught.

[rinagoldfield]

Great explanation, Sumukh09!

[sujin91]

Thank you for your explanation. I chose answer choice E. could you explain why E is incorrect? Thank you

[sujin91]

Thank you for your explanation. I chose answer choice E. could you explain why E is incorrect? Thank you

[sumukh09]

Sure.

E doesn't help explain why the number of rose beetles would increase with only 1 trap installed. When the bag gets filled to capacity and beetles escape, the number of beetles in the garden would still be the same. We want to know why the number of rose beetles would increase with only one trap - E doesn't provide us with information that would enable us to reason why the number of rose beetles would increase.

[danifarahi]

Can someone please give reasons as to why the answers are correct or incorrect? and is the answer D? Sorry, confused!

[LejlaM266]

I chose (A) because I understood it to say that because the rose beetles cannot detect the single trap's scent, they are not lured and killed, and so are able to spread and reproduce without anything lowering their numbers. Therefore their number increases. Yes, you would have to make an assumption that the time period they are talking about is long enough so that the rose beetles could spread and increase. But for (D) you would have to assume that just because one trap attracts more beetles than it can catch that it ultimately won't catch any beetles at all. If the capacity for trapping beetles is 10, and it attracts 20, why would it be reasonable to assume that the trap will not catch even one out of the 20? I don't see how (D) is a better answer.

[Laura Damone]

Let's start by talking about the correct answer, D. D tells us that any number of traps will attract more beetles than 1 trap can catch. That means that if you have 1 trap, it will attract more beetles than it can catch, leading to a net increase in the total number of beetles. This is true without any assumptions. That's why it's the right answer.

Say a trap can catch at most 10 beetles. If any number of traps will attract more than 10 beetles, 1 trap will attract at least 11 beetles. It can trap at most 10. That leaves 1 more beetle than there was in the garden before the trap was installed. Make sense?

You're right that A works if you assume that the period if observation is long enough for the beetles to breed. That said, you'd also have to assume that these beetles increase their population with each breeding cycle. Since we don't know the rate of death vs. the rate of birth, this is also an assumption.