Logical reasoning PrepTest 142 · Section 1 · Question 15

Incorrect. The bacterial infection concentration rate went up after the treatment was administered—i.e., after the several weeks it took to administer it. What matters is what happened after it was administered, not before/during.

Incorrect. Those levels were still lowered by this treatment, and we still have no explanation for the higher levels of other bacteria.

Incorrect. We're trying to explain something that happens while they're still chicks and undergo this treatment, however, so what happens much later is out of scope.

Incorrect. If anything, this makes the unexplained outcome worse—why are the untreated chicks with lower concentrations of these bacteria seeing a higher level of illness from that bacteria?

Correct. Argument or Facts:
Facts

Question Type:
Paradox

Stimulus Summary:
Problem Ð Salmonella makes people sick, and chickens have salmonella
Solution Ð A new treatment that decreased salmonella rate in young chicks
Unexpected outcome Ð A week later, the treated chicks had a higher amount of a variety of bacteria

Answer Anticipation:
The stimulus focuses on a treatment that had a certain effect—it lowered the rate of Salmonella infection in chicks. It also had an unexpected outcome—those chicks, a week later, had a higher concentration of a variety of other bacteria. This unexpected outcome is what we're tasked with explaining.

While we don't want to put on our scientist hats (lab coats?) because, well, we're not scientists, we can still approach this question based on its logic rather than content. The treatment changed something about the chicks, and we know two outcomes—it lowered Salmonella rates, and it increased other bacteria rates a week later. The correct answer is going to have to highlight what changed that would explain those higher concentrations of other bacteria.

To take it a step further, we already know about one change! The treatment lowered Salmonella levels. If the Salmonella was keeping the other bacteria at bay, that would explain why removing it led to an increase in those levels.

Answer Explanation:
This answer focuses on explaining the higher levels of bacteria based on a change we know happened in this population. The treatment gets rid of some amount of Salmonella, so if that bacteria was keeping the others at bay as this answer suggests, then it would make sense getting rid of it would result in the other bacteria increasing.

Key Takeaway:
When there's an unexpected outcome to a change introduced, that's generally the element that needs explaining in a Paradox question. Whatever change was introduced brought with it something that led to the unexpected outcome. And if the expected outcome was also present—here, the lowering of Salmonella—and it makes sense that that drove the unexpected result, then the correct answer may very well connect those two outcomes.