25. CR Inference / conclusion
Must be true from the passage alone. Softer claims win; extreme wording loses.
Core ideas
- The answer must be provable from the passage alone; no outside knowledge, no plausible extras.
- Softer wording wins: "some", "at least one", "may" are easier to prove than "most", "all", "will".
- Combine two stated facts; the credited inference is usually their overlap.
- Kill choices with new comparisons, predictions, or recommendations the passage never makes.
Worked example 1
All of the apartments in the Kestrel Building were built before 1960. Every apartment built before 1960 in this city uses steam heating. Some apartments in the Kestrel Building have been renovated within the past five years.
Which must be true?
(A) Renovated apartments no longer use steam heating.
(B) At least some apartments with steam heating have been renovated within the past five years.
(C) Most steam-heated apartments in the city are in the Kestrel Building.
Show solution
Chain the facts: all Kestrel apartments are pre-1960, and all pre-1960 apartments use steam heat, so every Kestrel apartment uses steam heat. Some Kestrel apartments were recently renovated, and those apartments use steam heat, so some steam-heated apartments were recently renovated. That is exactly (B), a soft "at least some" claim fully derivable from the overlap. (A) adds an unstated effect of renovation, and (C) makes a "most" comparison across the whole city that the passage cannot support. Answer: (B).
Worked example 2
The Halloway Aquarium feeds its otters twice daily. On days when attendance exceeds 2,000 visitors, the afternoon feeding is moved to the outdoor pool. Yesterday the otters' afternoon feeding took place indoors.
Which must be true?
(A) Yesterday's attendance did not exceed 2,000 visitors.
(B) The otters were fed only once yesterday.
(C) Attendance yesterday was unusually low.
Show solution
The rule says high attendance forces the afternoon feeding outdoors. Yesterday it was indoors, so the trigger condition cannot have held: attendance did not exceed 2,000. That is the contrapositive, and it proves (A). (B) contradicts the stated twice-daily schedule. (C) overreaches: at most 2,000 could still be normal or even high for the aquarium; "unusually low" is an extra judgment the passage never supports. Extreme or added claims lose; the minimal contrapositive wins. Answer: (A).
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