LSAT Question Stem

The official's conclusion is most strongly supported if which one of the following groups of trees did not show a reduction in losses of fruit to insects? 

Logical Reasoning Question Type

This is a Strengthen question. 

Correct Answer

The correct answer to this question is C. 

LSAT Question Complete Explanation

The question type for this problem is Strengthen, which means we are looking for an answer choice that will provide additional support for the official's conclusion.

Let's first analyze the argument in the passage. The local agricultural official gave the District 10 Farmers' Cooperative a new pesticide for their pear orchards, which they used for three years. During this time, the proportion of pears lost to insects was significantly less than during the previous three-year period when they used the old pesticide. The official concludes that the new pesticide is more effective than the old one, at least in the short term, in limiting the loss of certain fruits to insects.

The argument's structure can be broken down as follows:

Premise: The new pesticide was used for three years, and the proportion of pears lost to insects was significantly less than with the old pesticide.

Conclusion: The new pesticide is more effective than the old one, at least in the short term, in limiting the loss of certain fruits to insects.

An "Evaluate" question for this argument could be: "Were there any other factors, besides the change in pesticide, that could have contributed to the reduction in pears lost to insects during the three-year period?"

Now let's discuss the answer choices:

a) Peach trees grown in the district that were treated with the new pesticide instead of the old pesticide.

This answer choice does not strengthen the official's conclusion because it involves a different type of fruit (peach) and does not allow us to directly compare the effects of the old and new pesticides on pear trees.

b) Peach trees grown in the district that were treated with the new pesticide in addition to the old pesticide.

This answer choice does not help the official's conclusion since both pesticides were used, making it impossible to determine which one was responsible for any reduction in losses of fruit to insects.

c) Pear trees grown in the district that were treated with the old pesticide instead of the new pesticide.

This is the correct answer choice. If pear trees treated with the old pesticide did not show a reduction in losses of fruit to insects, but those treated with the new pesticide did, then it supports the conclusion that the new pesticide is more effective.

d) Pear trees grown in a neighboring district that were treated with neither the old nor the new pesticide.

This answer choice does not support the official's conclusion, as it does not allow us to compare the effects of the old and new pesticides since neither was used on these trees.

e) Pear trees grown in a neighboring district that were treated with the new pesticide instead of the old pesticide.

This answer choice does not support the official's conclusion because it does not allow us to directly compare the effects of the old and new pesticides. The lack of reduction in losses of fruit to insects could be due to factors specific to the neighboring district, and not the pesticides themselves. Furthermore, since only the new pesticide was used, we cannot compare its effects to those of the old pesticide.