They only know their own names?
There are three children in a park: Adam, Bree, and Charles. All 3 of them know that they have distinct surnames and distinct favorite colors. However, since none of them wants to reveal their own surname and favorite color to the others, they only know each other by their first name. Bree claims that her surname is not Clinton and her favorite color is not red.
Adam then immediately figures out everyone's surnames and favorite colors.
Question 1
: Is Charles's surname Clinton?
Question 2
: Is Charles's favorite color orange?
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1 solution
Assuming that Bree is telling the truth, then if Adam's name is Clinton then he would have no clue as to how to assign the other two surnames to Bree and Charles. Thus the only way he can immediately figure out the surnames is if he also is not a Clinton, in which case he knows his own surname, (not Clinton), Bree's surname, (not Clinton or his own surname), and that Charles' surname is Clinton.
If Bree's favourite colour is not red and Adam's is, then he would have no idea how to assign the remaining two colours to Bree and Charles. Thus his favourite colour can't be red, and since Bree's isn't red either that must mean that Charles' favourite colour is red, and not orange. Adam would then know his favourite, and also know that Bree's favourite is the remaining of the three colours, i.e., not red or his own.