The Sum and the Product
Two integers x and y satisfy 1 < x < y and x + y ≤ 100. S is told their sum and P is told their product. P: "I don't know the numbers." S: "I knew you didn't." P: "Now I know them." S: "Now I know them too." What are x and y?
Related problems & prerequisites
Worth solving first
- Cheryl's Birthday 7.0/10
- The Twelve Balls 7.0/10
- The Fly and the Trains 6.0/10
Source: The Impossible Puzzle, posed by Hans Freudenthal (1969). Statement written for AxiomIQ.