LSAT 139 | Section 1 | Logical Reasoning: Q15

LR Question 15 Explanation

QUESTION TEXT: To reduce the mosquito population in a resort area…

QUESTION TYPE: Paradox

PARADOX: We planted trees to attract birds. The birds eat mosquitos, but there are more mosquitos than ever.

ANALYSIS: Mosquito population depends on many factors. It’s the number of births minus the number of deaths. You have to look at all the causes of birth rate and death rate.

So yes, birds kill some mosquitos. But maybe the birds and fruit also attracted animals that mosquitos
feed on.

The right answer says that the birds eat the mosquitos’ predators, reducing the mosquitos’ death rate.

Several of the wrong answers mentioned that not all the birds eat mosquitos. This doesn’t matter, because some birds eat mosquitos. That would normally reduce population, not increase it.

___________

1. It doesn’t matter if most birds don’t eat mosquitos. Some of the birds do eat mosquitos. We would expect that to reduce the population, not increase it.
2. This is practically the same as A. It doesn’t matter if all the birds eat mosquitos, as long as some of them did. We would expect the birds to decrease the population of mosquitos as long as some birds ate mosquitos. Instead the mosquito population increased.
3. CORRECT. If this is true, then mosquitos got lucky. The birds ate their predators. So while a few mosquitos die from birds, many more survive due to lack of predators.
4. This makes things even weirder. We would expect the dry weather to kill mosquitos. Instead, there are more mosquitos.
5. This is just a useless fact. We don’t know what part of the cycle we’re in. If we are in an increasing part of the cycle, this could explain things. If we are in a decreasing part, this makes things more confusing.