ANSWERS A-23 55. a) m C 50 100 150 250 200 Cost ($) C 5 0.20m 1 80 100 300 400 500 200 Miles Cost of Operating a Taxi b) $110 c) 120 miles 56. y 4 24 x 22 4 24 (2, 1) (1, 0) (0, 21) (5, 0) 3x 2 3y 5 3 x 1 3y 5 5 (0, ) 5 3 57. x y 2 22 (21, 3) 22 4 2x 1 4y 5 4 x 1 2y 5 5 Inconsistent (0, 1) (2, 0) (5, 0) 58. (3, 1) 59. − − ( 1, 5) 60. − − ( 2, 8) 61. No solution; inconsistent 62. − (4, 2) 63. An infinite number of solutions; dependent 64. − (2, 1) 65. (2, 0) 66. $250,000 at 3%, $150,000 at 6% 67. Mix 831 3 of 80% acid solution with 16 2 3 of 50% acid solution. 68. a) 32.5 months b) Model 6070B 69. a) 3 hr b) All-Day parking lot 70. x y 2 4 22 2 4 22 24 6 (0, 4) (6, 0) 2x 1 3y # 12 71. x y 2 4 6 8 2 4 22 24 22 24 (0, 6) (3, 0) 4x 1 2y $ 12 72. x y 2 22 22 6 4 2 6 8 4 (4, 7) 2x 1 y , 8 y $ 2x 2 1 (0, 8) (4, 0) (0, 21) 73. x y 22 2 6 8 2 4 22 24 x 2 y . 5 6x 1 5y # 30 (0, 6) (0, 25) (5, 0) 74. a) (0, 4) 2 4 6 2 4 6 8 x y (3, 2) (4, 0) (0, 0) b) Maximum is 21 at (3, 2); minimum is 0 at (0, 0). 26. x x( 15,000) 75,000; $30,000 + + = for B and $45,000 for A 27. 1 2 cup 28. 250 min, or 4 hr 10 min 29. 72 30. 4 31. 20 32. 426.7 ≈ 33. $3150 34. $119.88 35. 24 36. 16 37. 29 28 27 26 25 21 0 1 23 24 22 38. 210 211 29 28 27 26 25 21 0 1 2 3 4 5 6 23 24 22 39–42. 2 4 6 y x 22 22 24 24 2 4 6 41 39 42 40 43. x y 2 2 22 24 22 24 4 4 x 2 y 5 2 (2, 0) (0, 22) (1, 21) 44. x y 2 22 24 22 2x 1 3y 5 12 (3, 2) (6, 0) (0, 4) 2 4 6 45. 24 22 2 4 6 2 22 x y (0, 23) (6, 0) x 2 2y 5 6 46. 24 22 2 4 4 24 22 x y (0, 24) (3, 0) 4x 2 3y 5 12 47. 4 3 48. − 3 2 49. 7 3 50. Undefined 51. x y 2 22 4 22 24 24 y 5 2x 2 5 (0, 25) (1, 23) 2 52. x y 2 2 4 26 22 24 4 2y 2 4 5 3x (0, 2) (2, 5) 53. = + y x2 4 54. = − + y x 1
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