Posts by Kuai

Total # Posts: 994

  1. Math

    -16(t^2-4t-12) =0 (t-6)(t+2) =0 t - 6 = 0 t = 6
  2. Math

    x^2 -25 =0 (x -5)(x+5) =0
  3. Intermediate Algebra for College

    y = 0 0= .25x + 15 -15 = .25x x = -60 x =0 y= .25(0) + 15 y = 15 Slope is .25 (-60,0),(0,15)
  4. statistics

    alpha = a= 0.05 Z0.025 = 1.96 p = 0.5 q = 1-p = 0.5 E = 0.05 Effect size = 384.16 n = 385
  5. statistics

    P(x < 113) mean = 125 Standard deviation = sqrt(variance) Standard deviation = 5 z = (113-125)/5 z = -12/5 z = -2.4 P ( z < -2.4) = 0.0082
  6. math pls help!!!!!

    1. C 2. D 3. B 4. A
  7. Statistics 1

    z = (score -mean)/sd z = (2500 -2500)/500 z = 0 is 50%
  8. Algebra

    Hank and Rashad are walking the Appalachian Trail from Maine southward through Maryland for a distance of 1164 miles. They have walked three times as many miles as they have remaining. How many miles are there remaining for them to walk?
  9. Math

    (x + 79 + 84 + 68)/4 = 80 (x + 231)/4 =80 x +231 = 320 x + 231- 231 = 320-231 x = 89 Fourth test 89
  10. algebra

    x = liters of 37% acid solution Other = (50 - x) = liters of 27% solution 37x + 27*(50 - x) = 50*36 37x + 1350 - 27x = 1800 10x = 450 x = 45 liters 45 liters of 37% acid and 5 liters of 27% acid.
  11. math

    Adult: a Children: c a + c = 450 70a + 40c = 27750 Substitute c = 450 -a 70a + 40(450 - a) = 27750 70a + 18000 -40a = 27750 30a + 18000 = 27750 30a + 18000- 18000= 27750-18000 30a = 9750 30a/30 = 9750/30 a = 325 c = 450 -a c = 450-325 c = 125
  12. Math Help!

    1. 2x(10x) = 20x^2 2. You can check because if -3m(m + 8) -3m(m-8) = -3m^2 + 24m 3. 4d(2d - 9) = -8d^2 - 36d
  13. algebra 2

    Standard error = sd/√n = 0.75/√35 = 0.12677 This is not algebra
  14. Algebra

    13a + 9b -2a -4b 13a -2a + 9b - 4b = 11a + 5b
  15. Statistics/Probability

    Exp = 1(.35) + 2(.4) + 3(.1) + 4(.15) = .35 + .8 + .3 + .6 = 2.05 Variance = 1^2 (.35) + 2^2(.4) + 3^2(.1) + 4^2(.15) = .35 + 1.6 + .9 + 2.4 = 5.25 Sd = sqrt(5.25-(2.05)^2) = 1.02
  16. statistic

    Phat = 500/1200 phat =0.4167 E = 1.96 * sqrt(.4167*.5833/1200) E = 0.0279 0.4167 -+ 0.0279 [0.3888, 0.4446]
  17. Maths (Integration)

    (1+x/x^3)dx = x -1/x + c
  18. Math 8th Grade!!!!

    27 -18/3 * (-4)-0-33-(-39) 27-6* (-4) - 0 - 33 -(-39) =27 + 24 -0 -33 + 39 =51-33 + 39 = 5$
  19. math 8th grade

    -15- (3-7) + 6 *(-2) +(-8) -9 = -15-(-4) +(-12) - 8 -9 =-15 + 4 -12 -8 -9 = -11 -12 -8 -9 =- -40
  20. math--check my answer

    37, 38, 39, 41, 43, 47, 52, 54 Yes
  21. statistics

    80 * .2 16
  22. Stats Psychology

    6 * 10 = 60 (60-y)/9 = 5 60-y = 45 60-45 = y 15 = y The value of the score that was removed 15
  23. Algebra

    Z = (score-mean)/SD -1.7 = (13-18.1)/SD -1.7 = -5.1/SD -1.7SD = -5.1 SD = -5.1/-1.7 SD = 3.0
  24. algebra

    Oj: x Apple juice: (8-x) .25x + .75(8-x) = .4(8) .25x + 6 -.75x = 3.2 6 -0.5x = 3.2 -.5x = 3.2-6 -.5x = -2.8 x = 5.6
  25. Statictics

    Mean = np = 25(.2) = 5 Standard deviation = sqrt((25 * .2*.8)) = 2
  26. MATH HELP ASAP

    B
  27. Statistics

    Phat = 44/50 = .88 mean of error Sqrt(.88* .12/50) = ?
  28. Algebra

    A = p( 1 + r/n)^t*n t = 3.5*2 = 7 r = 0.08/2 = 0.04 A = 25000( 1+ 0.04)^7 A = 25000( 1.04)^7 A = $32,898.29
  29. math

    y = mx + b f(x) = 2m + b = 1 f(x) = 4m + b = 0 f(x) = 6m + b = -1 -1(2m + b = 1) 4m + b = 0 -2m -b = -1 4m + b = 0 2m = -1 m = -1/2 2(-1/2) + b = 1 -1 + b = 1 -1+ 1 + b = 1 + 1 b = 2 y = mx +b y = -1/2x + 2
  30. math

    c = 10n + 26 n = 27 n = 39 n = 43 c = 10 ( 27) + 26 c = 270 + 26 c = 296 so you can finish the rest.
  31. statistics

    20/36
  32. statistics

    (1- .98)/2 = .01 = 2.33
  33. algebra/stressed

    There is typo for simple interest Simple interest. =Prt = 32500(.069)(3) =$6,727.50 Amount. = p + interest A = $ 32500 + $6727.50 A = 39,227.50
  34. algebra/stressed

    a) annually A = p(1+ r)^t A = 32500(1+ 0.069)^3 A = 32500(1 .069)^3 A = $39,702.37 b) semiannually A = p(1+ r/n)^tn A = 32500(1 + 0.069/2)^(3*2) A = 32500(1.0345)^6 A = $39,835.14 c) quarterly A = p(1+ r/n)^tn A = 32500( 1+ 0.069/4)^(3*4) A = 32500(1.01725)^12 A = $39,903.94 d...
  35. Algebra

    A = p(1 + r)^t 60000 =p(1.03)^30 60000 = 2.427262471p P = $24719.21
  36. Statistics

    Range = max -min Range =102 -77 Range = 25 Standard deviation = 8.56
  37. ALGEBRA

    mean = 9.3, median = 10, mode = 13
  38. Statistics

    n = (z/2 )^2 * pq/E^2 n = (1.96)^2 *0.82*0.18/0.04^2 n = ?
  39. Algebra ck to see if I did it correclty please

    6^x = 6^2 x = 2 2^x = 2^2 x = 2 3^x = 3^4 x = 4 ok
  40. Math

    m = (-20-(-11))/(5-2) m = -9/3 m = -3 y -(-11) = -3(x -2) y + 11 = -3x + 6 y + 11 -11 = -3x + 6 -11 y = -3x - 5
  41. Geometry

    Yes
  42. Algebra 1 Answer Evaluation

    (x - 3)^2 = 22 x - 3 =-+√(22) 3-√(22), 3+√(22)
  43. Algebra

    6^x = (1/6)^2 6^x = 6^-2 x = -2 3^x = 8 Log3^x = log8 x log3 = log8 x = log8/log3
  44. algebra

    P(1+ r/n)^tn 8000(1+.12/2)^2*2 8000(1.06)^4 =?
  45. Algebra

    y-1/x+3=-3/4 y-1/x+ 1/x + 3-3 = -3/4 + 1/x -3 y - 0 + 0 = -3/4 - 3 + 1/x y = (-3 - 12)/4 + 1/x y = -15/4 + 1/x
  46. Math

    bracelet = x Necklace = 5x x + 5x = 192 6x = 192 6x/6 = 192/6 x = 32 Necklace = 5x = 5(32) = 160
  47. Math Help

    A = l*w l = 2w -1 120 = (2w-1)w 120 = 2w^2 -w 2w^2 -w -120 = 0
  48. Math

    0/2, 4/12, 2/3, 5/6, 9/9
  49. math

    Adult: x Student: y x + y = 90 12x+ 8y = 980 12x +8(90-x) = 980 12x + 720 -8x = 980 4x = 260 x = 65 y = 25
  50. Algebra

    A = LW L = w-1 120 =(w-1)w 120 = w^2-w w^2-w-120 =0
  51. Pre-algebra

    P=2l+2w 70 = 2(17) + 2w 70 = 34 +2w 70-34 = 34-34 +2w 36 = 2w w = 18
  52. Math

    A) $1629.53 x 0.195 x 21/365 = $18.28 B) $2639. 99 * .2295 * 30/365 = $49.80
  53. Economics (36)

    a. What is the probability that the debt for a randomly selected borrower with good credit is more than $18,000 (to 4 decimals)? p(x > 18000) z = ( x - μ ) / σ z = (18000 -15015)/3730 z =2985/3730 = 0.8 P( z > 0.8) = 1-.7881= 0.2119 b. What is the probability ...
  54. Economics (42)

    You're welcome.
  55. Economics (42)

    n=20, xbar= 126, s=63.94 a=0.05, |t(0.025, df=n-1=19)|= 2.09 So 95% CI is xbar ± t*s/√n 126 ± 2.09*63.94/√(20) (96.1, 155.9)
  56. Math

    Ok
  57. Math

    y = mx + b f(x) = 2m + b = 1 f(x) = 4m + b = 0 f(x) = 6m + b = -1 -1(2m + b = 1) 4m + b = 0 -2m -b = -1 4m + b = 0 2m = -1 m = -1/2 2(-1/2) + b = 1 -1 + b = 1 -1+ 1 + b = 1 + 1 b = 2 y = mx +b y = -1/2x + 2
  58. math

    67=(3-6x)/4.13 67(4.13) = 4.13(3-6x)/4.13 276.71 = 3-6x 273.71 = -6x x = 273.71/-6 x = -45.618
  59. Math

    y = mx + b f(x) = 4m + b = 2 f(x) = m + b = -4 4m + b = 2 -m -b = 4 3 m = 6 m = 2 4(2) + b = 2 8 + b = 2 b = -6 y = 2x - 6
  60. MAth

    4. (1-5)/(3-6) = 4/3 5. (-6-(-5)/(-3-(-3) -1/0 Undefined
  61. algebra

    x = 7-(1/8)y x-7 = -1/8y -8x+56 =y
  62. Stats

    n = [(z-value * sd)/E]^2 n =[ (2.575 * 42)/3]^2
  63. Economics (45)

    The 2003 Statistical Abstract of the United States reported the percentage of people 18 years of age and older who smoke. Suppose that a study designed to collect new data on smokers and nonsmokers uses a preliminary estimate of the proportion who smoke of .30. a. How large a ...
  64. Economics (41)

    A) z = 1.96 n = 60 x-bar = 96 S = 16 SE = σ/√n = 16/√60 xbar ± z*s/√n 96 ± 4.048 ( 92.0, 100.0) B) z = 1.96 SE = σ/√n = 16/√120 96 - 2.867, 96 + 2.867 (93.1, 98.9)
  65. Economics (41)

    I did not know how to do it.
  66. Economics (41)

    Only c is correct
  67. Economics (40)

    A market research firm conducts telephone surveys with a 42% historical response rate. What is the probability that in a new sample of 400 telephone numbers, at least 150 individuals will cooperate and respond to the questions? In other words, what is the probability that the ...
  68. Economics (39)

    39) Suppose a random sample of size 40 is selected from a population with σ = 9. Find the value of the standard error of the mean in each of the following cases (use the finite population correction factor if appropriate). a. The population size is infinite (to 2 decimals...
  69. Economics (37)

    37) According to the Sleep Foundation, the average night's sleep is 6.8 hours (Fortune, March 20, 2006). Assume the standard deviation is .7 hours and that the probability distribution is normal. a. What is the probability that a randomly selected person sleeps more than 8...
  70. Math

    .8/1.6 = .5 .4/.8 = .5 .2/.4 = .5 Constant Geometric
  71. Algebra

    Let t = time required by the larger pipe alone then 3t = time required by the smaller pipe alone Let the completed job = 1; (a full tank) Each pipe will fill a fraction of the tank, the two fractions add up to 1. 9/t + 9/3t = 1 27 + 9 = 3t 36 = 3t 12 = t Large pipe :12 hours ...
  72. math

    y = mx + b f(x) = 2m + b = 1 f(x) = 4m + b = 0 f(x) = 6m + b = -1 -1(2m + b = 1) 4m + b = 0 -2m -b = -1 4m + b = 0 2m = -1 m = -1/2 2(-1/2) + b = 1 -1 + b = 1 -1+ 1 + b = 1 + 1 b = 2 y = mx +b y = -1/2x + 2
  73. Calculus

    (1/3x^3)-x^2+x-1 when x=1 F'(x) = x^2 -2x + 1 F'(1) = 1-2+ 1 = 0 f(x) = 1/3-1+ 1 -1 f(x) =( 1-3+3-3)/3 f(x) = -2/3 y - (-2/3 ) = 0(x -1) y + 2/3 = 0 y = -2/3
  74. Algebra

    -1/3 > -3
  75. math

    Ho: u1-u2 = 0 Ha: u1-u2 is not 0 test-statistic = -3.8563 p-value = 0.00038 df = 43 Conclusion:Since p-value is less than alpha=5%, Reject Ho. There is at difference in the average cost of couches at these two stores.
  76. Math

    Yes total bands: 185 P(pink) = 95/185 = 19/37 P(brown) = 90/185 =18/37
  77. math

    9x - 7y =4 -7y = -9x + 4 y = 9x/7 - 4/7 Slope of line parallel: 9/7 Slope of line perpendicular: -7/9
  78. math

    =1/(-2x)^6 = 1/64x^6
  79. math

    (a^4b^6)^0 = 1
  80. Algebra

    W=√1/LC W^2 = 1/LC LCW^2 = 1 L = 1/CW^2
  81. algebra

    Logb(a) = c Log1/5(25) = 2
  82. math

    90 minutes = 1.5 hrs 45 minutes = 0.75 hrs 8*5 - (1.5 + 0.75 + 2.5 ) 40 - 4.75 35.25 = 35 1/4 hours = 35 hours and 15 minutes
  83. math

    Width of pool is x+3 Length of pool is 3x-4 Width of deck is 3x-2 Length of deck is 2x+6 area= (2x+6)(3x-2) - (3x-4)(x+3) = 6 x^2 + 14 x -12 -[ 3x^2 +5 x -12 ] = 3 x^2 + 9 x 110.4375
  84. math

    Wrong answer
  85. math

    90 minutes = 1.5 hrs 45 minutes = 0.75 hrs 8*5 - (1.5 + 0.75 + 2.5 ) 40 - 4.75 35.25 = 35 1/4 hours = 35 hours and 15 minutes
  86. Statistics

    n = 30 x = 31.5 μ = 32 SEm = SD/√n SEm = 4/√30 SEm = 0.73 z = ( x - μ ) / SEm z = (31.5-32)/0.73 z = -0.68 P(z < -0.68) = 0.2483
  87. ALGEBRA

    • 13 in, 84 in, 85 in
  88. Math

    (2/5)(3/8) = 6/40
  89. Algebra

    (z + 3)(z +15)
  90. stat

    9C2(.17)^2(.83)^7
  91. algebra

    Let x: 5 bill let y: 10 bill x + y = 25 5x + 10y = 230 5x + 10(25-x) = 230 5x + 250 -10x = 230 -5x = -20 x = 4 y =21
  92. statistics 101 college

    phat = 8/28 = 0.286
  93. Algebra Question~!

    A= P(1+r)^t 16099.44= 15000(1+r)^2 16099.44/15000 = (1+r)^2 sqrt((16099.44/15000) = 1+ r sqrt(166099.44/1500) -1 = r r = 3.6%
  94. ALGEBRA

    1 -15 = 36x -72 -14 +72 =36x 58 =36x 58/36 = x 29/18 = x
  95. math

    850(1+.15/12)^48 = 1543.o516 Monthly payment 1543.0516/48 = $32..15
  96. math

    All correct except 5 #5 is d
  97. Math

    3x+6y=6 2x-3y=9 3x + 6y = 6 2(2x -3y =9) 3x + 6y = 6 4x -6y = 18 7x = 24 x = 24/7 y =-30/7
  98. Math

    -1(5x+7y=77 ) -5x -7y = -77 5x+3y=53 -4y = -24 y = 6 5x + 3(6) = 53 5x + 18 = 53 5x = 35 x = 7
  99. economics (4)

    (1/.2)* 40 = $200 billion
  100. math (5)

    a) dp/dx = -.032x + y + 28 = -.032(4000) + 150(1) + 28 = -128 + 150 + 28 = 50 dp/dy = -34y + x + 22 = -34(150) + 4000(1) + 22 = -5100 + 4000+ 22 = -1078 b) dp/dx = -.032x + y + 28 = -.032(5000) + 150(1) + 28 = -160 + 150 + 28 = 18 dp/dy = -34y + x + 22 = -34(150) + 5000(1) + ...
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