2012_Answer_Key.pdf

MATHCOUNTS

®

2012 State Competition Answer Key The appropriate units (or their abbreviations) are provided in the answer blanks. Answers to the Tiebreaker Tiebreaker Round  problems appear in the Tiebreaker Tiebreaker Round Booklet. Note to coordinator coordinators: s:

National Sponsors Raytheon Company * U.S. Department of Defense *  Northrop Grumman Foundation Foundation *  National Society of Professional Professional Engineers * Bezos Family Foundation * ConocoPhillips * CNA Foundation * Texas Instruments Incorporated * ThinkFun * 3M Foundation

2012 MATHCOUNTS National Competition Sponsor

Founding Sponsors: National Society of Professional Engineers, National Council of Teachers of Mathematics and CNA Foundation Foundation

Copyrightt MATHCOUNTS, Copyrigh MATHCOUNTS, Inc. 2011. 2011. All rights reserved. 03-S12ANS

Sprint Round

50 minutes 1. _____________ 

20 units2 8. _____________ 

18 2. _____________ 

1355 seconds 9. _____________ 

121 circles 14. _____________ 

 pairs 1 15. _____________ 

20 diagonals 3. _____________  4 10. _____________  7 units 16. _____________ 

1 27 4. _____________ 

cm 10 5 11. _____________ 

10 edges 5. _____________ 

2 6. _____________ 

hours 3 17. _____________ 

560 12. _____________  98,751 18. _____________ 

3.25 7. _____________  1003 13. _____________  unit 30 19. _____________  cubes

Copyright MATHCOUNTS, MATHCOUNTS, Inc. 2011. 2011. All rights reserved. 2012 State Answer Key

Sprint Round 5

69 20. _____________ 

3 units 26. _____________ 

3 21. _____________  cm

1800 ways 27. _____________   x + 1 22. _____________ 

2 28. _____________  81 units2 23. _____________ 

27 subsets 29. _____________ 

5

126 30. _____________ 

2 24. _____________ 

203 25. _____________ 

Copyright MATHCOUNTS, MATHCOUNTS, Inc. 2011. 2011. All rights reserved. 2012 State Answer Key

Target Round 3 $ 2.10 1. ________________ 

8 3. ________________ 

329 students 5. ________________ 

1462.5 % 7. ________________ 

5

8 values 2. ________________ 

15 4. ________________ 

1.07 cm 6. ________________ 

9 8. ________________ 

Copyright MATHCOUNTS, MATHCOUNTS, Inc. 2011. 2011. All rights reserved. 2012 State Answer Key

Team Round tickets 450 1. _____________ 

ways 360 6. _____________ 

( 6 , 4 ) 7. _____________ 

$5.00 or $5 2. _____________ 

3.78 minutes 8. _____________  12 3. _____________ 

937.5 4. _____________  ft2 9. _____________  3230

15 5. _____________  cm3 10. _____________  912π

Copyright MATHCOUNTS, MATHCOUNTS, Inc. 2011. 2011. All rights reserved. 2012 State Answer Key

Countdown Round

1. _________________  14

21. _________________  93

2. _________________  20

22. _________________  8

3. _________________  38

23. _________________  589

4. _________________  1

24. _________________  16,460

5. _________________  2600 (codes)

25. _________________  2.5

6. _________________  48 (cm)

26. _________________  4000 (weights)

7. _________________  3

27. _________________  60

8. _________________  200

28. _________________  24 (arrangements)

9. _________________  8 (units2)

29. _________________  4 (triangles)

10. _________________  117

30. _________________  81

11. _________________  8

31. _________________  (Number) 5

12. _________________  7

32. _________________  47 2

2

13. _________________  45 (units )

33. _________________  5

14. _________________  259

34. _________________  242 (cm2)

15. _________________  5

35. _________________  5

16. _________________  66 (objects)

36. _________________  5

17. _________________  18 (years)

37. _________________  8

1

1

18. _________________  16

38. _________________  25

19. _________________  2

39. _________________  50

5

20. _________________  7

40. _________________  675 (integers)

Copyright MATHCOUNTS, MATHCOUNTS, Inc. 2011. 2011. All rights reserved. 2012 State Answer Key

Countdown Round

15 (degrees) 41. _________________ 

−96 61. _________________ 

405 42. _________________ 

8 62. _________________ 

12 43. _________________ 

24 63. _________________  2

60 (degrees) 44. _________________ 

64. _________________  3

1 45. _________________ 

5 65. _________________ 

6 46. _________________ 

14 (line segments) 66. _________________ 

8 (locations) 47. _________________ 

−2 67. _________________ 

11 48. _________________ 

9a b  (units) 68. _________________ 

6 2

1

26 (units) 49. _________________ 

69. _________________  2

(8, −9) 50. _________________ 

27 70. _________________ 

30 (percent) 51. _________________ 

667 (dollars) 71. _________________ 

25 (days) 52. _________________ 

2100 (cm) 72. _________________  1

(Day) 28 53. _________________ 

73. _________________  6

5 54. _________________ 

2 74. _________________ 

3 5 55. _________________ 

.8 or 0.8 (percent) 75. _________________ 

40 (chips) 56. _________________ 

9 (times) 76. _________________ 

3

57. _________________  4

28 (questions) 77. _________________ 

201 58. _________________ 

84 78. _________________ 

16

59. _________________  55

59 79. _________________ 

−10 60. _________________ 

4 80. _________________ 

Copyright MATHCOUNTS, MATHCOUNTS, Inc. 2011. 2011. All rights reserved. 2012 State Answer Key