Cards with the numbers 7,8,9,4,5,6,1,2 and 3 are laid in a row in the indicated order.It is permitted to choose several consecutive cards and rearrange them in the reverse order. Is it possible to obtain the arrangement 1,2,3,4,5,6,7,8,9 after 3 such operations? Source: Question 21 of Chapter 8(P...

175 Humpties cost more than 126 Dumpties. Prove that you cannot buy three Humpties and one Dumpty for one dollar. I found this question in the book mentioned below. This question seem to have flaws. Because if each Humpty costs 25 cents and each Dumpty costs 25 cents then we don't violate any ...

I found this puzzle in an online test and I think the answer is E, the pentagon with no lines inside it because the last column always has at most as many lines as the first column. I can't think of a better explanation. What do you think is the right answer?

Here's a story I just made up: "Ethan, a curious soul with a deep passion for both the stars and music, had always found harmony between the two. Earlier that evening, he had aligned his telescope using the Prime Meridian, ensuring perfect calibration for his observations. Precision mattered, and...