Review practice
Choose a section to work through its questions and solutions. Your progress is shared across pages. Ranges follow collection order; original source labels are kept on each question.
Section 1 · Questions 1–6
Choose people while controlling complete couples · Separate fixed digit counts from adjacent-repeat complements · +4 more
- Question 1 · Choose people while controlling complete couples
- Question 2 · Separate fixed digit counts from adjacent-repeat complements
- Question 3 · Allow leading zero in a six-position PIN
- Question 4 · Choose three gaps for the three vowels
- Question 5 · Distinguish nine-digit integers from nine-position binary strings
- Question 6 · Count adjacency in the row and circle as disjoint cases
Section 2 · Questions 7–12
Split repeated-vowel endpoints into disjoint cases · Treat the buildings as fixed labelled objects · +4 more
- Question 7 · Split repeated-vowel endpoints into disjoint cases
- Question 8 · Treat the buildings as fixed labelled objects
- Question 9 · Use a manager as the circular reference
- Question 10 · Use flavour multiplicities rather than physical bar identities
- Question 11 · Keep the meeting and lunch seating models separate
- Question 12 · Separate labelled circular seats from fixed-room colour assignments
Section 3 · Questions 13–16
Keep committee choices, circular seating and diner choices distinct · Explain every complement and the meaning of neighbouring ride seats · +2 more
- Question 13 · Keep committee choices, circular seating and diner choices distinct
- Question 14 · Explain every complement and the meaning of neighbouring ride seats
- Question 15 · Split a parent–child–parent block by its table
- Question 16 · Reserve the central front-row positions before placing the children