Question 1
SEAMO self-study edition 2027; not an official 2027 paper. Original source years are retained. 25 questions, 90 minutes; Q1–10: 3 points, Q11–20: 4 points, Q21–25: 6 points, total 100. Original response types and all subparts are preserved. Verified is an editorial convention; source defects, necessary assumptions and unresolved mathematical uncertainty are disclosed.
The diagram shows a circular track with diameter $AB$. Alejandro starts at $A$ and Behzod at $B$. They walk towards each other around the track, first meeting at $C$, 80 m from $A$, then meeting again at $D$, 60 m from $B$. Find the circumference in metres.
Use the usual constant-speed model: both keep walking in their original directions, and the stated distances are along the indicated shorter arcs.
The diagram shows a circular track with diameter $AB$. Alejandro starts at $A$ and Behzod at $B$. They walk towards each other around the track, first meeting at $C$, 80 m from $A$, then meeting again at $D$, 60 m from $B$. Find the circumference in metres.
Use the usual constant-speed model: both keep walking in their original directions, and the stated distances are along the indicated shorter arcs.