Free practice · boolean · medium
Practice
Apply a valid contrapositive
A rule says: if a request is approved, its approval field is signed. Request B's approval field is not signed. Therefore, Request B is not approved.
Deduction chain
Preserve direction from premises to conclusion
- PremisesSeparate facts and rules
- DirectionMark if, only, all, and some
- ConnectLink matching terms
- ChallengeTry a counterexample
- ConcludeState only what is guaranteed
A guaranteed conclusion follows only when stated facts activate rules in their written direction and no counterexample survives.