Mary and her number
Source: Tournament of Towns, Fall 2002, Junior O Level, P2
May 15, 2014
number theory proposednumber theory
Problem Statement
John and Mary select a natural number each and tell that to Bill. Bill wrote their sum and product in two papers hid one paper and showed the other to John and Mary.
John looked at the number (which was ) and declared he couldn't determine Mary's number. Knowing this Mary also said she couldn't determine John's number as well.
What was Mary's Number?