• Cade has six red stamps and three blue ones.
• In his collection, seven stamps are from Argentina and six stamps are from Sweden.
• One stamp is purple and it is not from Argentina or Sweden.
• Two of his Argentine stamps are red and one is blue.
• Two of his Swedish stamps are blue and three are red.

I had calculated fifteen, as well. But then decided to do a bit of thinking outside the mental mailbox...

There is no given that any of the numbers given are the exact number for the color and nation. These may be interpreted as minimums. And, though one usually interprets an 'or' in grammar as an exclusive disjunction unless there is a verbal inflection, it is still a possibility that a logical disjunction -- especially in logic, as is the puzzle category -- could be meant. And, even further a minimal can be found by interpretting the question, "What is the minimum number of stamps that Cade can have?". As the question is not explicitly asking how many, under the givens, does Cade have, and, as Cade can always be rid of the collection, the answer can be zero.

Posted by Dej Mar on 2014-11-07 10:39:12