x implies y - solutions Part I: Frobby? Question summary: Black triangle, white triangle, black circle, and white circle.  Given a chosen object, "frobby" items share either shape OR color, but not both.  White triangle is frobby.  What else is? Answer: You can get thrown off here because you do NOT have enough info to tell what the "chosen" object is.  You just know it's either white OR a triangle, but not both.  The chosen object is either the black triangle or the white circle.  So -- neither of those is frobby, because those objects either match BOTH shape and color, or neither.  And the black circle IS frobby (since it will also share either shape OR color). Part II Question summary: 4 letter/number cards show as 2 5 F E.  Rule: a card with an odd number on one side must have a vowel on the other.  How many cards do we flip to see if the rule is true? Answer: Read the rule carefully -- it's very specific, and only affects cards that have an odd number on one side.  It does NOT require consonants matched with even numbers, and a vowel does not require an odd number! So: 2: don't flip; no odd number 5: flip; must have vowel F: flip; may have an odd number (which would require a vowel here) E: don't flip - we know we have a vowel. You need to flip two cards. jtheory Thursday, January 29, 2004 I don't know why that's supposed to be hard; I guess I've taken too many object oriented tests and the answers are just about always like this one. Len Williams Sunday, February 15, 2004 its not hard but it prompts the person to make mistake in first go...as ppl forget to pick f , vivek jain Tuesday, March 16, 2004   Fog Creek Home