LSAT (Law School Admission Test)Analytical ReasoningMedium
A journalist is interviewing six politicians—P, Q, R, S, T, U—for an article. Each politician will be interviewed exactly once, in a sequence from first to sixth. The interviews must conform to the following conditions: 1. P must be interviewed before Q. 2. R must be interviewed immediately after S. 3. T must be interviewed fourth. 4. U cannot be interviewed first or last. Which of the following is a complete and accurate list of the politicians who could be interviewed first?
- AP, R
- BS, U
- CP, S
- DP, S, U
Show answer & explanationAnswer & explanation
Correct answer: C. P, S
T is fixed in fourth position. U cannot be first or last. R must be immediately after S, so R cannot be first. P must be before Q, so Q cannot be first. If U is first, then U violates rule 4. This leaves P and S as the only possible politicians for the first position.
Why the other options are wrong
- A. R cannot be first because it must be immediately after S.
- B. U cannot be first due to rule 4.
- D. U cannot be first, making this list inaccurate.
First Position Possibilities (Complex)
Determining all items eligible for the first position in a sequence, involving multiple interacting ordering, grouping, and exclusion rules.
- Requires careful consideration of all types of constraints.
- Systematic elimination of candidates is essential.
- Often involves checking for direct contradictions or impossibility of fulfilling subsequent rules.
Memory trick: First in line, who's got the green light?