# High School Challenge

## Week Ending 10-31-99

### Congratulations to Cristina Domnisoru from Orono High School in Orono, ME. Cristina wins the Casio CFX-9850G Color Graphing calculator.

Weigh Those Blocks

Suppose you have a double pan balance and 37 blocks. All 37 blocks appear to be the same. Thirty-six of the blocks weigh exactly the same amount and the remaining one slightly heavier. You are unable to identify the heavy one by lifting the individual blocks. What is the fewest possible number of weighings you would need to make to guarantee that the heavy block could be identified, no matter how many times you repeated the activity? This balance is capable of holding as many of the blocks on each side as you would like to use. Putting blocks on both sides constitutes one weighing. Adding or removing blocks from that situation would be considered a second weighing.

### Correct Solutions:

1. Michael Moyer. The Way Home School, Carlisle, PA
3. Jeffrey Mo. University ES, Calgary, AB, Canada
4. John Pinto. Bishop Moore HS, Orlando, FL
5. Kenny Yu. SKH Lam Woo Memorial SS, Hong Kong
6. Sorin Ionescu. John Abbot College, Montreal, Canada
7. Anton Lukyanenko. Evans JHS, Lubbock, TX
8. Jason Juang. Sycamore JHS, Cincinnati, OH
9. Alex Shim. Framingham HS, Framingham, MA
10. Jongmin Baek. Hyde JHS, Cupertino, CA
11. David Held. Miami Sunset HS, Miami, FL
12. Eric Hoke. Wayland HS, Wayland, MA
13. Tao Chen. Miller MS, San Jose, CA
14. Michael Cheung. SKH Lam Woo Memorial SS, Hong Kong
15. Jan Nordbotten. Cathedral School, Bergen, Norway
16. Simon Rubinstein-Salzedo. Homestead HS, Cupertino, CA
17. Matan Protter. Ort Kiryat Bialik, Kiryat Bialik, Israel
18. Loc Thai. Rostrevor College, Adelaide, SA, Australia
19. Brian Clary. Louisa County HS, Mineral, VA
20. John Xia. Torrance High School, Torrance, CA
21. Jeremy Wilson. Newport Harbor HS, Newport Beach, CA
22. Nate Ince. Homeschooled, Arnold, MO
23. Tiffany Chao. Seaquam SS, Delta, BC, Canada
24. Eric Tsai. Columbus High, Columbus, GA
25. Michael Guzik. Guzik Learning Center, San Diego, CA
26. Sean Ervin. Jackson Memorial HS, Jackson, NJ
27. Lee Colbert. Jackson Memorial HS, Jackson, NJ
28. Nick Mauro. Jackson Memorial HS, Jackson, NJ
29. Matt Whitmore. Jackson memorial HS, Jackson, NJ
30. Brian Nicolletti. Jackson Memorial HS, Jackson, NJ
31. Andrey Mamontov. Reedsburg HS, Reedsburg, WI
32. Nathan French. Windsor HS, Windsor, VT
33. Rohan Mathew. Sycamore JHS, Cincinnati, OH
34. Kevin Chan. Seminole HS, Sanford, FL
35. Hongyi Li. Westmount HS, Montreal, QC, Canada
36. Pradeep Baliga. Central HS, Tuscaloosa, AL
38. Tuna Tasdelen. Ozel A.Aymaz Okulu, Konya, Turkey
39. Ozlem Tasdelen. Maresal M.Kemal Okulu, Konya, Turkey
40. Thomas Lee. The Meadows School. Las Vegas, NV
41. Daniel Gee. Stone Valley MS, Alamo, CA
42. Angela Christmas. Louisa County HS, Mineral, VA
43. Mike Apple. Louisa County HS, Mineral, VA
44. Robbie Lane. Louisa County HS, Mineral, VA
45. Sean Nelson. Louisa County HS, Mineral, VA
46. Hayley Johnson. Louisa County HS, Mineral, VA
47. Jason Lewis. Louisa County HS, Mineral, VA
48. Dawn Gordon.Louisa County HS, Mineral, VA
49. C.T. Thiemann. Louisa County HS, Mineral, VA
50. Melissa Carroll. Louisa County HS, Mineral, VA
51. Halsey Green. Louisa County HS, Mineral, VA
52. Jeremy Sestito. Louisa County HS, Mineral, VA
53. Ashley Coleman. Louisa County HS, Mineral, VA
54. Jason Hicks. Louisa County HS, Mineral, VA
55. Daniel Yu. Randolph MS, Randolph, NJ
56. Ismar Tuzovic, St John Bosco College, Engadine, NSW, Australia
57. Michael Tso. St. Michael's University, Victoria, BC, Canada
58. Nicholas Assanis. Greenhills School, Ann Arbor, MI
59. Jenny Laaser. JL Stanford MS, Palo Alto, CA
60. Karen Wong. Southwood SS, Cambridge, ON, Canada
61. Xuan Wu. John W. North HS, Riverside, CA
62. Mike Munson, Newport Harbor HS, Newport Beach, CA
63. Evelyn Cheung. Mayfield HS, Pasadena, CA
64. Samuel Timothy Dy. St. Stephen's HS, Manila, Philippines
65. Sarah Reuter. Sauk Centre HS, Sauk Centre, MN
66. John Tullos. North Delta HS, Batesville, MS
67. Elena Udovina. The Agnon MS, Beachwood, OH
68. Mark Vos. Constantia Waldorf School, Cape Town, South Africa
69. Kyle Bentfield. Sauk Centre HS, Sauk Centre, MN
70. Ben Conlee. Albuquerque Academy, Albuquerque, NM
71. Shih-Fan Yeh. Burlingame HS, Burlingame, CA
72. Brad Chapin. John W. North HS, Riverside, CA
73. Jessica Kneubuhl. Airline HS, Bossier City, LA
74. Joe Park. The Meadows School, Las Vegas, NV
75. Rachel Chan. UHS, Ontario, Canada
76. Guy David. Ransom MS, Miami, FL
77. Phongtharin Vinayavekhin. Bodindacha, Bangkok, Thailand
78. Crsitina Domnisoru. Orono HS, Orono, ME