Publications by Quoc Tran
2020-05-15-Classic
Riddler Classic By Zach Wissner-Gross Since it was impossible to complete the game of sudoku, you might instead enjoy passing the time with a game of Dungeons & Dragons, courtesy of Emma Knight: The fifth edition of Dungeons & Dragons introduced a system of “advantage and disadvantage.” When you roll a die “with advantage,” you roll the ...
2405 sym R (2273 sym/11 pcs) 4 img
2020-05-01-Classic
Riddler Classic By Zach Wissner-Gross From Bart Wright comes a rhetorical question from a famed soliloquy, “To flip, or not to flip?”: You are locked in the dungeon of a faraway castle with three fellow prisoners (i.e., there are four prisoners in total), each in a separate cell with no means of communication. But it just so happens that all...
2634 sym R (1522 sym/6 pcs) 3 img
2020-03-27-Classic
Riddler Classic By Zach Wissner-Gross From Chris Nho comes a question of rolling (and re-rolling) a die: You start with a fair 6-sided die and roll it six times, recording the results of each roll. You then write these numbers on the six faces of another, unlabeled fair die. For example, if your six rolls were 3, 5, 3, 6, 1 and 2, then your seco...
1106 sym R (746 sym/4 pcs) 1 img
2020-03-13-Express
Riddler Express By Zach Wissner-Gross Most people will tell you that a kilobyte is 1,000 bytes, that a megabyte is 1,000,000 bytes and that a gigabyte is 1,000,000,000 bytes. But that’s not quite right — a kilobyte is in fact 1,024, or \(2^{10}\), bytes. A megabyte is 1,048,576, or \(2^{20}\), bytes. A gigabyte is 1,073,741,824, or \(2^{30}\...
1102 sym R (640 sym/3 pcs) 1 img
2020-03-13-Classic
Riddler Classic By Zach Wissner-Gross Sticking with the board game theme, from Andrew Lin comes a closer examination of a classic game of reasoning and elimination: This week’s Riddler Classic is a new take on a recent puzzle. Two weeks ago, you were waiting in line at a barbershop. There were four barbers working simultaneously, and each hair...
3245 sym R (1816 sym/4 pcs) 1 img
2020-02-28-Classic
Riddler Classic By Zach Wissner-Gross From Dave Moran comes a question we’ve all faced at some point when waiting in line for a haircut: At your local barbershop, there are always four barbers working simultaneously. Each haircut takes exactly 15 minutes, and there’s almost always one or more customers waiting their turn on a first-come, fir...
4101 sym R (2344 sym/6 pcs) 2 img
2020-02-21-Classic
Riddler Classic By Zach Wissner-Gross From Abijith Krishnan comes a game of coin flipping madness: You have two fair coins, labeled A and B. When you flip coin A, you get 1 point if it comes up heads, but you lose 1 point if it comes up tails. Coin B is worth twice as much — when you flip coin B, you get 2 points if it comes up heads, but you ...
2399 sym R (1680 sym/6 pcs) 1 img
2020-02-07-Express
Riddler Express By Zach Wissner-Gross From James Anderson comes a palindromic puzzle of calendars: This past Sunday was Groundhog Day. Also, there was a football game. But to top it all off, the date, 02/02/2020, was palindromic, meaning it reads the same forwards and backwards (if you ignore the slashes). If we write out dates in the American f...
1416 sym
2020-01-17-Classic
Riddler Classic By Zach Wissner-Gross After a long night of frivolous quackery, two delirious ducks are having a difficult time finding each other in their pond. The pond happens to contain a 3×3 grid of rocks. Every minute, each duck randomly swims, independently of the other duck, from one rock to a neighboring rock in the 3×3 grid — up, d...
1412 sym R (1096 sym/3 pcs) 1 img
2020-01-10-Classic
Riddler Classic By Zach Wissner-Gross From Leonard Cohen comes a puzzle at the intersection of language and mathematics: In Jewish study, “Gematria” is an alphanumeric code where words are assigned numerical values based on their letters. We can do the same in English, assigning 1 to the letter A, 2 to the letter B, and so on, up to 26 for t...
1892 sym R (2477 sym/6 pcs) 1 img