Vamshi Jandhyala
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Mathematical writing · The Riddler

Contents

290 chapters. Problems are from FiveThirtyEight's The Riddler column; all solutions are my own.

  1. 1The Honest Prince and the Rancher’s Children
  2. 2Can You Knock Down The Last Bowling Pin?
  3. 3Can You Find Your Pills?
  4. 4Can You Make Room For Goats?
  5. 5How Long Will Your Smartphone Distract You From Family Dinner?
  6. 6Will The Neurotic Basketball Player Make His Next Free Throw?
  7. 7Night Falls. A Storm Rolls In. Can You Cross The River?
  8. 8How Many Cars Will Get Stuck In Traffic?
  9. 9Will Someone Be Sitting In Your Seat On The Plane?
  10. 10Should You Pay $250 To Play This Casino Game?
  11. 11Should You Shoot Free Throws Underhand?
  12. 12Can You Slay The Puzzle Of The Monsters’ Gems?
  13. 13Can You Solve This Elevator Button Puzzle?
  14. 14The Puzzle Of Misanthropic Neighbours
  15. 15You Have $1 Billion To Win A Space Race. Go.
  16. 16Should The Grizzly Bear Eat The Salmon?
  17. 17How Long Will It Take To Blow Out The Birthday Candles?
  18. 18Who Steals The Most In A Town Full Of Thieves?
  19. 19Pick Up Sticks And Help A Frogger Out
  20. 20How Do You Like Them Rectangles?
  21. 21Will You Be A Ghostbuster Or A World Destroyer?
  22. 22Palindrome Senates and an Ancient Tiling
  23. 23Where Will The Seven Dwarfs Sleep Tonight?
  24. 24Help Us Find These Missing Pieces
  25. 25When Will The Arithmetic Anarchists Attack?
  26. 26World Cup Standings and Number Shuffling
  27. 27Can You Win The Token Game?
  28. 28What Share Of Your Gummy Vitamins Are The Right Flavor?
  29. 29The Eternal Question: How Much Do These Apricots Weigh?
  30. 30What Are The Odds You’d Already Have My Number?
  31. 31What Comes After 840? The Answer May Surprise You
  32. 32How Low Can You Roll?
  33. 33How Many Ways Can You Raid The Candy Shop?
  34. 34Who Wants To Be A Riddler Millionaire?
  35. 35Can You Track The Delirious Ducks?
  36. 36Can You Find A Number Worth Its Weight In Letters?
  37. 37Can You Solve The Vexing Vexillology Of Spelling Bee?
  38. 38Can You Find A Matching Pair Of Socks?
  39. 39Can You Get A Haircut Already?
  40. 40How Good Are You At Guess Who?
  41. 41What Is The First Flipper’s Advantage?
  42. 42Can You Find The Best Dungeons & Dragons Strategy?
  43. 43Can You Tell When The Snow Started?
  44. 44Can You Flip The Magic Coin?
  45. 45When Is The Next Centered Pentagonal Flag?
  46. 46Breaking A Slide Rule Into Four Pieces
  47. 47Can You Reach The Summit First?
  48. 48How Close To The Bullseye Can Robin Get?
  49. 49Can You Hunt For The Mysterious Numbers?
  50. 50Can You Skillfully Ski The Slopes?
  51. 51How Far Down Does The Little Cube Reach?
  52. 52Can You Randomly Move The Tower?
  53. 53Can You Cross Like A Boss?
  54. 54En Garde! Can You Win The Fencing Relay?
  55. 55Can You Slice The Ice?
  56. 56Can You Stick It To The Genie?
  57. 57How Many Friends Are On The Riddler Social Network?
  58. 58Can You Survive Squid Game?
  59. 59Who Betrayed Dune’s Duke Leto?
  60. 60Can You Climb Your Way To Victory?
  61. 61Can You Bake The Radish Pie?
  62. 62Can You Get The Paper Cut?
  63. 63Can You Draft A Riddler Fantasy Football Dream Team?
  64. 64Can You Catch The Cricket?
  65. 65Are You Clever Enough?
  66. 66Will Riddler Nation Win Gold In Archery?
  67. 67Can You Hop Across The Chess Board?
  68. 68Can You Win The Penalty Shootout?
  69. 69Can You Solve This Astronomical Enigma?
  70. 70Can You Decipher The Secret Message?
  71. 71Can You Crack The Case Of The Crystal Key?
  72. 72No Isosceles Triangles For You!
  73. 73Can You Systematically Solve A Friday Crossword?
  74. 74Can You Cut The Perfect Pancake?
  75. 75Can You Crack The Case Of The Crescent Moon?
  76. 76Can You Navigate The One-Way Streets?
  77. 77Can You Find An Extra Perfect Square?
  78. 78Can You Bake The Biggest Pie?
  79. 79Can You Bat .299 In 299 Games?
  80. 80How Many Ways Can You Build A Staircase?
  81. 81Can You Win Riddler Jenga?
  82. 82Can You Find The Luckiest Coin?
  83. 83Work A Shift In The Riddler Gift Shop
  84. 84It’s Elementary, My Dear Riddler!
  85. 85Can You Fold All Your Socks?
  86. 86Can You Salvage Your Rug?
  87. 87Can You Make The Fidget Spinner Go Backwards?
  88. 88When Will The Fall Colors Peak?
  89. 89Can You Knock Down The Gates?
  90. 90How Many Turkey Trotters Can You Pass?
  91. 91Can You Win The Riddler Football Playoff?
  92. 92Random Walk from the Centre of a Unit Square and Cube
  93. 93What’s The Best Way To Drop A Smartphone?
  94. 94Which Geyser Gushes First?
  95. 95How Long Before You Can Use Your 2015 Calendar Again?
  96. 96How Badly Can A Car Salesman Swindle You?
  97. 97Who Will Win The Politicians’ Secret Vote?
  98. 98Will The Dog Catch The Duck?
  99. 99Can You Decode The Four Secret Messages?
  100. 100Can You Win This Hot New Game Show?
  101. 101Can You Best The Mysterious Man In The Trench Coat?
  102. 102Can You Solve The Impossible Puzzle?
  103. 103Can You Solve This Napoleonic Puzzle?
  104. 104The Perplexing Puzzle Of The Proud Partygoers
  105. 105Can You Solve The Puzzle Of The Overflowing Martini Glass?
  106. 106Can You Solve The Puzzle Of The Baseball Division Champs?
  107. 107Can You Solve The Puzzle Of The Pirate Booty?
  108. 108Solve The Mystery Of The Mathematical Mistakes
  109. 109Can You Solve The Puzzle Of The Picky Eater?
  110. 110What If Robots Cut Your Pizza?
  111. 111Can You Figure Out How To Beat Roger Federer At Wimbledon?
  112. 112Can You Save Riddler Headquarters From Laser Larry?
  113. 113How Long Will You Be Stuck at the Bar?
  114. 114Stop the Alien Invasion
  115. 115Sniff Out the Traitorous Generals
  116. 116The Pokémon Go Trainer’s Round Trip
  117. 117Outrun the Angry Ram
  118. 118The Particular Mathematician’s Cake
  119. 119Bananas to the Bazaar
  120. 120Who Keeps the Money on the Floor?
  121. 121How High Can the Count Count?
  122. 122The Carpenter’s Circular Table
  123. 123Cubs Win-Strings and a Risk-Free Bet
  124. 124Pawns, Knights, and Fairy Pieces
  125. 125Flipping Coins and a Deadly Board Game
  126. 126Growing Words and a Point-Rich Boggle Board
  127. 127A Rickety Bridge and One Decisive Vote
  128. 128Couples in a Line and the Lonesome King
  129. 129Championship Droughts and Secret Santas
  130. 130A Suspicious Tournament and a Gold-Hungry War
  131. 131Misplaced Rocks and Tangled Wires
  132. 132Scaling a Death Star and Outgunning Stormtroopers
  133. 133A Doomed Solitaire and Baby Poker
  134. 134A Reusable Calendar and the Game of Hip
  135. 135Tetris Tilings and a Splitting Microbe
  136. 136The Lifeguard’s Dash and Toddler Poker
  137. 137Counting Honest Politicians and Burning Ropes
  138. 138Two Mysteries of the Gold Coins
  139. 139The Biggest Number and the Corn Maze
  140. 140Who Will Win the Space Race?
  141. 141The Toddler at the Couch and the Ten Dwarves
  142. 142Lunch in the Park and the Crowded Chessboard
  143. 143Two Cards at Lunch and the Multiplication Game
  144. 144Bingo Cards and the Empty Supreme Court
  145. 145Temperature Records and Picking The Highest Card
  146. 146Three Hat-Wearing Logicians and Four Repainting Balls
  147. 147Mrs. Perkins’s 13-by-13 Quilt and the Lucky Derby
  148. 148Carpool Tickets
  149. 149Best-Of-Seven and the First-Price Auction
  150. 150The Barron Square and Four Sealed Checks
  151. 151Three Birthday Pairs and Chaos Tag
  152. 152Letter-Lengths and the Caffeine Contest
  153. 153Pursuit on the Shore and Ranking Films
  154. 154Crescents, Footballs, and the Squishyball Series
  155. 155Ballots, Primaries, and the Spy in Riddler Nation
  156. 156Lowest Unique Number and the Factor Chain
  157. 157Is This Bathroom Occupied?
  158. 158Can You Plug The White House Leak?
  159. 159Can You Unravel These Number Strings?
  160. 160Is Your Friend Full Of It?
  161. 161Four Aces Against The Deck
  162. 162Rock, Paper, Scissors, Double Scissors
  163. 163Three Daughters And One Hundred Boxes
  164. 164A Perfect Game Of Jeopardy And A Game Of Coinball
  165. 165Can You Please The Oracle? Can You Escape The Prison?
  166. 166The Twenty-Five Horses And The Price Is Right
  167. 167Four Puzzles From Riddler Nation’s Students
  168. 168Inside The Cube And The Three-Lock Safe
  169. 169The Perfect Darts Game
  170. 170The Count Counts Higher, and Equations Hidden in Digits
  171. 171Two Holiday Puzzles
  172. 172A Triangle, A Tetrahedron, And A Circle’s Centre
  173. 173Picture Frames That Crash To The Floor
  174. 174The Dodgeball Truel
  175. 175Doppler Cars and Conway’s Shuffle
  176. 176Yahtzee Strategy
  177. 177Bollier Numbers
  178. 178Nightmare Klondike
  179. 179Shut the Box
  180. 180How To Cross The Street
  181. 181How Fast Can You Type A Million Letters?
  182. 182Pirates, Monkeys, and Coconuts
  183. 183How Hard Is It To Find A Running Buddy?
  184. 184When Will Your House Collapse? Should You Take A Construction Contract?
  185. 185The Case Of The Smudged Secret Message
  186. 186How Many Phones Do You Need To Win HQ Trivia?
  187. 187The Riddler’s Inaugural Rock-Paper-Scissors Tournament
  188. 188What Are The Odds World Cup Teams Play Each Other Twice?
  189. 189How Fast Can You Deliver PB&Js? How Many Meerkats Can Survive?
  190. 190Can You Slice This In Half?
  191. 191Damn The Torpedoes, Two Puzzles Ahead!
  192. 192The Perfect Doodle Puzzle To Keep You Busy During Boring Meetings
  193. 193Where On Earth Is The Riddler?
  194. 194Step 1: Game Theory. Step 2: Step 3: Profit!
  195. 195How Many Hoops Will Kids Jump Through To Play Rock, Paper, Scissors?
  196. 196The New National Pastime: Competitive Coin Flipping
  197. 197I’d Like To Use My Riddler Lifeline
  198. 198To Solve The Eccentric Billionaire’s Puzzle, You Must First Defeat The Banker
  199. 199Two Paths Diverged In A City And I, I Took The Block Less Traveled By
  200. 200The Robot Invasion Has Come For Our Pool Halls
  201. 201How Much Will It Cost To Sniff Out The Spies?
  202. 202So You Want To Tether Your Goat. Now What?
  203. 203So Your Archipelago Is Exploding. How Doomed Is Your Island?
  204. 204Who Will Capture The Most James Bonds?
  205. 205How Far Would You Go To Rig A Coin Flip?
  206. 206The Riddler Just Had To Go And Reinvent Beer Pong
  207. 207Alice And Bob Fall In Love
  208. 208The Little, Mathematically Determined House On The Prairie
  209. 209Can You Win Tic-Tac-Toe Blindfolded?
  210. 210Santa Needs Some Help With Math
  211. 211What The Heck Are These Dang Bits?
  212. 212In Space, No One Can Hear Your 3D Printer Die
  213. 213How Many Crossword Puzzles Can You Make?
  214. 214Can You Escape A Maze Without Walls?
  215. 215525,600 Minutes Of Math
  216. 216Come On Down And Escape The Maze
  217. 217Don’t Trust Anyone Older Than L
  218. 218You’re Home Alone: Cigarette Cards And Bananagrams
  219. 219How Many Numbers Contain The Numbers Of Their Numbers?
  220. 220Can You Turn America’s Pastime Into A Game Of Yahtzee?
  221. 221Tickets Old And New, And A Spelling Bee Where Order Hardly Matters
  222. 222Free Drinks On Card Two
  223. 223How Many Times A Day Is A Broken Clock Right?
  224. 224How Many Earthlings Would Survive 63 Thanos Snaps?
  225. 225Are You The Best Warlord?
  226. 226Can The Riddler Bros. Beat Joe DiMaggio’s Hitting Streak?
  227. 227How Many Soldiers Do You Need To Beat The Night King?
  228. 228One Small Step For Man, One Giant Coin Flip For Mankind
  229. 229Can You Win The Lotería?
  230. 230You’ve Been Marooned By Kidnappers. Can You Escape At Dawn?
  231. 231How Inefficient Can You Make Your Walk To Class?
  232. 232I Would Walk 500 Miles And I Would Riddle 500 More
  233. 233Can You Win The Superstring Scrabble Challenge?
  234. 234What’s The Optimal Way To Play HORSE?
  235. 235Can You Construct The Optimal Tournament?
  236. 236Can You Escape This Enchanted Maze?
  237. 237How Many Cars Are On This Circular Train?
  238. 238Organize Some Debates! Maximize The Shade!
  239. 239Which Billiard Ball Is Rigged?
  240. 240Can You Fool The Bank With Your Counterfeit Bills?
  241. 241What Are Your Chances Of Winning The U.S. Open?
  242. 242Can You Help Dakota Jones Raid The Lost Arc?
  243. 243Can You Win The Tour de FiveThirtyEight?
  244. 244Which Baseball Team Will Win The Riddler Fall Classic?
  245. 245Can You Escape The Enemy Submarines?
  246. 246Can You Break The Riddler Bank?
  247. 247Can You Carve The Perfect Pumpkin?
  248. 248How Long Is The Snail’s Slimy Trail?
  249. 249Can You Decode The Riddler Lottery?
  250. 250How Fast Can You Skip To Your Favorite Song?
  251. 251Can You Solve A Particularly Prismatic Puzzle?
  252. 252How Many Pennies Should You Pinch?
  253. 253Can You Roll The Perfect Bowl?
  254. 254How Many More Palindrome Dates Will You See?
  255. 255Can You Solve This Rather Pedestrian Puzzle?
  256. 256Can You Flip Your Way To Victory?
  257. 257Can You Get Another Haircut Already?
  258. 258How Many Sets Of Cards Can You Find?
  259. 259Can You Get The Gloves Out Of The Box?
  260. 260Can You Catch The Free T-Shirt?
  261. 261Can You Solve The Chess Mystery?
  262. 262Can You Beat The GOAT Monty Hall Problem?
  263. 263Can You Flip Your Way To Freedom?
  264. 264Can You Eat An Apple Like A Toddler?
  265. 265Can You Find The Fish In State Names?
  266. 266Can You Join The World’s Biggest Zoom Call?
  267. 267Can You Pinpoint The Planet?
  268. 268How Long Will The Bacterial Colony Last?
  269. 269Can You Connect The Dots?
  270. 270Can You Stay In Your Lane?
  271. 271Can You Make 24?
  272. 272Can The Hare Beat The Tortoise?
  273. 273Are You A Pinball Wizard?
  274. 274Can You Cheat At Rock, Paper, Scissors?
  275. 275Can You Reach The Beach?
  276. 276Are You Hip Enough To Be Square?
  277. 277Can You Corral Your Hamster?
  278. 278Can You Cover The Globe?
  279. 279Can You Break A Very Expensive Centrifuge?
  280. 280Can You Save Some Cold Pizza?
  281. 281Can You Eat All The Chocolates?
  282. 282Can You Parallel Park Your Car?
  283. 283Is The Price Right?
  284. 284Can You Feed The Hot Hand?
  285. 285Beware The Hot Pumpkin
  286. 286Can You Make An Unfair Coin Fair?
  287. 287Can You Snatch Defeat From The Jaws Of Victory?
  288. 288Can You Pass The Cranberry Sauce?
  289. 289Can You Cut The Cookies?
  290. 290How High Can You Count With Menorah Math?