LSAT (Law School Admission Test)Analytical ReasoningMedium
A conductor is scheduling five musical pieces—Opus 1 (O1), Opus 2 (O2), Opus 3 (O3), Opus 4 (O4), Opus 5 (O5)—for a concert. Each piece will be played exactly once, in a sequence from first to fifth. The scheduling must conform to the following conditions: 1. O2 must be played immediately before O4. 2. O1 cannot be played first. 3. O5 must be played third. 4. O3 must be played at some point after O2. Which of the following is an accurate list of all pieces that could be played first?
- AO3, O4
- BO3
- CO3, O5
- DO4
Show answer & explanationAnswer & explanation
Correct answer: B. O3
O1 cannot be first (rule 2). O2 cannot be first because O3 must be after O2 (rule 4) and O2 must be immediately before O4 (rule 1), forming O2-O4 block. If O2 were first, O3 would have to be after O4, but there are only 5 positions. O5 must be third (rule 3), so O5 cannot be first. O4 cannot be first because it must be immediately preceded by O2 (rule 1). This leaves only O3 as a possibility for the first position.
Why the other options are wrong
- A. O4 cannot be played first because it must be immediately preceded by O2.
- C. O5 cannot be played first because it must be played third.
- D. O4 cannot be played first because it must be immediately preceded by O2.
First Position Possibilities
Determining which items are eligible to occupy the first position in a sequence, based on all given rules and constraints.
- Involves analyzing each item against all 'first position' related rules.
- Often requires considering blocks or relative ordering constraints.
- Process of elimination is key to narrowing down options.
Memory trick: Start Line: Who's in, who's out?