Peter's Book Return — Relay Chain Deduction

Peter has a book for Fiona but cannot see her today. He gives it to Zhang at 09:00. Meanwhile Sam→Tim at 10:00, Tim→Ursula at 11:00, Ursula→Fiona at 12:00. The right-hand chain is complete — but Zhang is isolated. The missing link is a meeting that connects Zhang into the chain before the chain moves on without the book.

Short 4–5 person relay questions with one obvious missing link appear regularly in the easier half of OC TS chain questions. The trap options always involve the right people but wrong timing (too early, too late, or the person doesn't have the object yet). Checking timing order is as important as checking who meets whom.

The examiner tests whether students can identify a gap in a relay chain (Zhang has the book but is disconnected from the Tim→Ursula→Fiona chain) and select the extra meeting that correctly bridges the gap with valid timing. Trap D (Zhang→Ursula at 12:30) is designed to catch students who ignore the timing — Ursula already met Fiona at 12:00.

An object (book, card, package) must travel from Person A to Person Z. Several meetings are scheduled but one link in the chain is absent. One extra meeting is needed to bridge the gap. Trap options include: meetings with wrong timing (too late or before the object arrives), meetings involving people outside the main chain, and meetings between the right people but where neither person has the object yet.