Happy Valentine's Day! On this most romantic of holidays, we tend to think of the most romantic things, like candle-lit dinners, long-stemmed roses, and brain-tickling puzzles. Because there really is nothing that brings you and your special someone together like logic puzzles.
I know what you're thinking: "Bring it on."
Marie and Pierre are nerds. Nerds in love. This Valentine's Day, Marie made Pierre a special gift but hid it in one of three labeled boxes. The red box had a label: "It's not in the green box." The green box had a label: "It's not in this box." And the blue box had a label: "It's in this box." Then, she added a twist; she told Pierre that at least one of the labels is true and at least one of the labels is false.
Where is Pierre's gift?
Ready for the answer?
It's easy to just walk through the three possibilities. Assume the gift is in each one of the boxes and count how many statements are true or false. If you assume the gift is in the red box, you get red: true, green: true, and blue: false. And we're already done! It's in the red box!
You can also deduce the answer logically from the labels. The labels on the red and green boxes are exactly the same statement, so those are either both true or both false. If they're both false, then the gift is in the green box, and the blue label would also be false. If they're both true, we'd need the blue label to be false, so the gift is in the red box.
Pretty easy, right? I hope you had a great Valentine's Day!
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