This problem was made by: Alex Bellos This is what it said:
Zebedee secretly writes down two consecutive positive integers. Then he tells one of the numbers to Xanthe, and the other number to Yvette (without telling them each other's number, but only telling their numbers are consecutive). The following conversation ensues:
Xanthe: "I don't know your number." Yvette: "I don't know your number." Xanthe: "Now I know your number!" Yvette: "Now I know your number!"
Which of the following must be one of the two numbers? 1,2,3,4,5 or it is not possible to answer. (answer was 3)
I wasn't sure wich was the correct answer. I am also not sure what a consecutive positive integer is. Could someone please explain how this problem works. Thanks!