EX 6 — Hub-and-spoke

This address has changed. On 2 October 2026 the fifteen numerical problems were put back in order of difficulty, and since then every page carries the name of the exercise in its address as well as the number: a reordering can no longer serve a different exercise at the same address without saying so.

• The exercise that used to be here, Hub-and-spoke, is now EX 4.
• This number today belongs to EX 6 — Vehicles with a minimum quantity.
• The full list of the fifteen problems is on the numerical problems page.