Good girls and bad boys (6)
On an island, there is this strange pattern - boys always lie while girls always tell the truth. You encounter three children.
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The oldest one says, "The number of boys is an even number."
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The middle one says, "The number of boys is an odd number."
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The youngest one says, "My two older siblings have the same gender."
Let 1 denote boys and 0 girls. In order of birth, identify the gender of each child and convert it into a number accordingly. Submit your answer as a string of 3 ones and/or zeroes. For example, if all three are boys, then your answer is 111.
The answer is 11.
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1 solution
Between the two older siblings, one must be telling the truth while the other must be lying as the number of boys is either even or odd. This means among them, one is a boy, the other a girl. This means the youngest child is lying. So the youngest child is a boy. Now we can tell in total we have two boys and one girl. So the number of boys is even. In other words, the oldest one is a truth teller (and hence a girl) while the middle one is a liar (and hence a boy).
Our desired answer is 011 (girl, boy, boy).