Unit 12 · Multi-Step Conditional Reasoning
Eye Colour Deduction — Contrapositive
Lesson 28 of 30
About this lesson
Five friends have either blue or brown eyes and each enjoy two activities. Two conditional rules link eye colour to activities. Q doesn't read → Q can't have brown eyes → Q has blue eyes. S only likes drawing (plus one more) → in every scenario, S ends up with blue eyes too. The key move is the contrapositive.
Chapters
Question
P, Q, R, S and T are friends. They all have either blue eyes or brown eyes. They each enjoy two of the following four activities: fishing, reading, playing the piano and drawing.
P likes reading and fishing. Q likes playing the piano and fishing. S likes drawing. Everyone likes fishing except one person with blue eyes. Everyone with brown eyes likes reading.
Which one of the following statements must be true?
Take your Selective prep further
- Sample questions & worked solutions across core Selective topics
- Digital exam simulator with interactive practice sets
- Personalised progress tracking across all your devices
Already have an account? Log in here
No payment required. Compare Selective plans
Give Your Child the Best Chance at Selective Entry
Join NSW families preparing their children for the Selective Schools Placement Test with the most realistic online Selective practice tests available. First tests free—no credit card required.
Claim Your Free Selective Practice Tests