This is the repo for https://play.google.com/store/apps/details?id=atorch.statspuzzles.
Nearly all of the puzzles in this app can be solved by hand, with pen and paper. For code that checks some of the answers using simulations (Monte Carlo), see https://github.com/atorch/probability_puzzles_solutions.
Are you looking for the puzzles? They're defined in app/src/main/res/values/strings.xml.