Elementary Brain Teaser


Send Answer to:mathed@pegasus.cc.ucf.edu



Crossing the River

An adult weighing 80 kilograms and 2 children, each of whom weighs 40 kilograms, want to cross a river. All 3 are capable of rowing the one boat they have. The boat is capable of holding only 80 kilograms on any one trip. How many trips will it take to get all 3 across a river? Describe your answer.




Correct Solutions:


  1. Miriam Lorbert. Shulamith School for Girls, Brooklyn, NY
  2. Erica Bell. St Mary Magdalen, Hazel Park, MI
  3. Wilson Fosgate. Lake Highland Prep, Orlando, FL
  4. Morana Golub. ES Lucko. Croatia
  5. Michael Allshouse. Briarhill MS, Highland Village, TX
  6. Tara Joensuu. Burt School, Waterford, MI
  7. Shane Lichtenberg. Burt School, Waterford, MI
  8. Dan Pace. Burt School, Waterford, MI
  9. Amanda Williams. Burt School, Waterford, MI
  10. Alex Carnacchi. Burt School, Waterford, MI
  11. Evan Howe. Burt School, Waterford, MI
  12. Jerrica Brown. Murphy Middle, Detroit, MI
  13. Danial Mapps. Murphy Middle School, Detroit, MI
  14. Marya Jefferson. Murph Middle School, Detroit, MI
  15. Carl Lake. Murphy Middle School, Detroit, MI
  16. Marvin Moultry. Murphy Middle, Detroit, MI
  17. Carol Glaser. Houston, TX. St. Thomas More
  18. Daniel Geary. Lake Highland Prep. Orlando,Fl
  19. E.B., Eliot Elementary School, Eliot, Maine
  20. Justin Richards. Burt School, Waterford, MI
  21. Chelsea Pieters. Burt School, Waterford, MI
  22. Ashley Goldberg. Jefferson School, Jefferson MA
  23. Jonathan Allain,Jefferson School,Jefferson,MA
  24. Ana Margarida. Escola 2/3 do Feijo, Almada, Portugal
  25. Claudia Lopes. Escola 2/3 do Feijo, Almada, Portugal
  26. Bruno Carvalho. Escola 2/3 do Feijo, Almada, Portugal
  27. Andr Rodrigues. Escola 2/3 do Feijo, Almada, Portugal
  28. Ana Rita Duarte. Escola 2/3 do Feijo, Almada, Portugal
  29. Gabriel Castanheira. Escola 2/3 do Feijo, Almada, Portugal
  30. Sara Duarte. Escola 2/3 do Feijo, Almada, Portugal
  31. Ana Patricia. Escola 2/3 do Feijo, Almada, Portugal
  32. Catia Mendes. Escola 2/3 do Feijo, Almada, Portugal
  33. Valter. Escola 2/3 do Feijo, Almada, Portugal
  34. Marcia Silva. Escola 2/3 do Feijo, Almada, Portugal
  35. Isabel Patricia. Escola 2/3 do Feijo, Almada, Portugal
  36. Pedro Chaby. Escola 2/3 do Feijo, Almada, Portugal
  37. Andrew Wagner. A.B. Dixon Elementary, Richmond, BC, Canada
  38. Calvin Yiu The King's Academy West Palm Beach, FL.
  39. Louis Tenebruso. Taylor Praire School, Cottage Grove, WI
  40. Catia Sofia. Escola 2/3 do Feijo, Almada, Portugal.
  41. Ruben Alexandre. Escola 2/3 do Feijo, Almada, Portugal.
  42. Angela Marisa, Escola 2/3 do Feijo, Almada, Portugal.
  43. Helena Zorro. Escola 2/3 do Feijo, Almada, Portugal.
  44. Robbe Harrison.Geneva Elementary,Geneva,FL
  45. Jason Strouse. Geneva Elementary, Geneva, FL
  46. Kimmy Corter. Geneva Elem. Geneva, FL
  47. Christi Miller. Geneva Elem. Geneva, FL
  48. Nicole McCall. Geneva Elem. Geneva, FL
  49. Heather Hughey. Geneva Elem. Geneva, FL
  50. Brian Pierre-Carmen Arace MS-Bloomfield, CT
  51. Rahim Muhammad-Carmen Arace MS-Bloomfield, CT
  52. Melissa Dreyer-Carmen Arace MS-Bloomfield, CT
  53. Shari Williams-Carmen Arace MS-Bloomfield, CT
  54. Mark Atkins-Carmen Arace MS-Bloomfield, CT
  55. Tao Tao Chen, Ellis ES, Sunnyvale, CA
  56. Daniel Oakes, Wells ES, Wells ME
  57. Danny Randolph. West Side ES, Powell, WY
  58. Vanessa de Armas. Kings Academy, West Palm Beach, FL
  59. Todd Miller. Alice C. Harris Intermediate,Tremonton, UT
  60. Pedro Rogerio. Escola 2/3 do Feijo, Almada, Portugal
  61. Alexandre Borges. Escola E.B.M. 508, Afonsoeiro, Montijo, Portugal
  62. Ana Sofia Troncao. Escola E.B.M. 508, Afonsoeiro, Montijo, Portugal
  63. Patricia Garcia. Escola E.B.M. 508, Afonsoeiro, Montijo, Portugal
  64. Luis Carlos Alves. Escola E.B.M. 508, Afonsoeiro, Montijo, Portugal
  65. Drew Hardwick. Farley ES, Huntsville, AL
  66. Ryan Cullen. The Sagemont School, Weston, FL
  67. Tommy Filliater. The Sagemont School, Weston, FL
  68. Nicky DeMarco. The Sagemont School, Weston, FL
  69. Danielle Singer. The Sagemont School, Weston, FL
  70. Heather Clark. Farley ES, Huntsville, AL
  71. Keith Mewis. Rideau Park ES, Richmond, BC, Canada
  72. Josh Brown. Wells ES, Wells, ME
  73. Kelley Schreiber. Sibley ES, Albert Lea, MN
  74. Justin Edge. Geneva ES, Geneva, FL
  75. Ryan Winowiecki. Schoolcraft School, Waterford, MI
  76. Mike Behrends. Sibley ES, Albert Lea, MN
  77. Ethan Berg. Sibley ES, Albert Lea, MN
  78. Ashley Erickson. Sibley ES, Albert Lea, MN
  79. David Knudson. Sibley ES, Albert Lea, MN
  80. Brandon Klukow. Sibley ES, Albert Lea, MN
  81. Seth Brua. Sibley ES, Albert Lea, MN
  82. Cody Schreiber. Sibley ES, Albert Lea, MN
  83. Andrew Stapleton. Sibley ES, Albert Lea, MN
  84. Ashley Erickson. Sibley ES, Albert Lea, MN
  85. David Knudson. Sibley ES, Albert Lea, MN
  86. Brandon Klukow. Sibley ES, Albert Lea, MN
  87. Seth Brua. Sibley ES, Albert Lea, MN
  88. Cody Schreiber. Sibley ES, Albert Lea, MN
  89. Gabriel Brondino. Escola 2,3 da Costa da Caparica, Almada, Portugal
  90. Nick Custodio. Pine Tree ES, Monroe, NY
  91. Claire Anderson. Bryan ES, Coeur d'Alene, ID
  92. Neil Wingkun. The King's Academy, West Palm Beach, FL
  93. Aaron Milton. The King's Academy, West Palm Beach, FL
  94. Christal Butler. The King's Academy, West Palm Beach, FL
  95. Stephen Shamakin. The King's Academy, West Palm Beach, FL
  96. Billy Gunter. The King's Academy, West Palm Beach, FL
  97. Alex Harmon Oblong Elementary School Oblong IL





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