Student Puzzle Corner
We pose a classic problem, variously known as the taxicab problem or the German tank problem (named after its historical application, by Allied forces in World War II, to the estimation of the monthly rate of German tank production from very few data). We have a finite population $\mathcal{X}$ with…

Contributing Editor Anirban DasGupta writes on the previous problem, which was about phase transitions: If the common probability that each observer tells the truth on any given instance is $p$, and if there are $m$ such observers, and if there are $n$ options (colors) to choose from, then by…

Congratulations to the two student members who sent correct answers to this puzzle: Yudong Chen (University of Cambridge, UK) and Zhen Huang (Columbia University, USA). Here’s Anirban DasGupta’s solution: Using the notation of the problem, the recorded values $Y_1, Y_2, \cdots$ are iid with \$E(Y_i) = \sum_{i =…