Question 13
A teacher chooses two numbers from 1,2,3,4,5,6. He tells Phong their product and Sang their sum.
Phong: “I know the product, but I cannot determine the two numbers.”
Sang: “I know the sum, but I cannot determine the two numbers either.”
Phong: “Then I now know the two numbers.”
What is their sum?
Model clarification: the two chosen numbers are distinct. Both pupils hear the whole dialogue, speak truthfully, make correct deductions and use all earlier statements.
Phong: “I know the product, but I cannot determine the two numbers.”
Sang: “I know the sum, but I cannot determine the two numbers either.”
Phong: “Then I now know the two numbers.”
What is their sum?
Model clarification: the two chosen numbers are distinct. Both pupils hear the whole dialogue, speak truthfully, make correct deductions and use all earlier statements.