# Posts by Kuai

Total # Posts: 994

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

Math
x^2 -25 =0 (x -5)(x+5) =0

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)

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

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

math pls help!!!!!
1. C 2. D 3. B 4. A

Statistics 1
z = (score -mean)/sd z = (2500 -2500)/500 z = 0 is 50%

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?

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

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.

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

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

algebra 2
Standard error = sd/√n = 0.75/√35 = 0.12677 This is not algebra

Algebra
13a + 9b -2a -4b 13a -2a + 9b - 4b = 11a + 5b

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

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]

Maths (Integration)
(1+x/x^3)dx = x -1/x + c

27 -18/3 * (-4)-0-33-(-39) 27-6* (-4) - 0 - 33 -(-39) =27 + 24 -0 -33 + 39 =51-33 + 39 = 5\$

-15- (3-7) + 6 *(-2) +(-8) -9 = -15-(-4) +(-12) - 8 -9 =-15 + 4 -12 -8 -9 = -11 -12 -8 -9 =- -40

37, 38, 39, 41, 43, 47, 52, 54 Yes

statistics
80 * .2 16

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

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

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

Statictics
Mean = np = 25(.2) = 5 Standard deviation = sqrt((25 * .2*.8)) = 2

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

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

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

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.

statistics
20/36

statistics
(1- .98)/2 = .01 = 2.33

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

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...

Algebra
A = p(1 + r)^t 60000 =p(1.03)^30 60000 = 2.427262471p P = \$24719.21

Statistics
Range = max -min Range =102 -77 Range = 25 Standard deviation = 8.56

ALGEBRA
mean = 9.3, median = 10, mode = 13

Statistics
n = (z/2 )^2 * pq/E^2 n = (1.96)^2 *0.82*0.18/0.04^2 n = ?

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

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

Geometry
Yes

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

Algebra
6^x = (1/6)^2 6^x = 6^-2 x = -2 3^x = 8 Log3^x = log8 x log3 = log8 x = log8/log3

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

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

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

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

Math
0/2, 4/12, 2/3, 5/6, 9/9

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

Algebra
A = LW L = w-1 120 =(w-1)w 120 = w^2-w w^2-w-120 =0

Pre-algebra
P=2l+2w 70 = 2(17) + 2w 70 = 34 +2w 70-34 = 34-34 +2w 36 = 2w w = 18

Math
A) \$1629.53 x 0.195 x 21/365 = \$18.28 B) \$2639. 99 * .2295 * 30/365 = \$49.80

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 ...

Economics (42)
You're welcome.

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)

Math
Ok

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

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

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

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

algebra
x = 7-(1/8)y x-7 = -1/8y -8x+56 =y

Stats
n = [(z-value * sd)/E]^2 n =[ (2.575 * 42)/3]^2

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 ...

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)

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

Economics (41)
Only c is correct

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 ...

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...

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...

Math
.8/1.6 = .5 .4/.8 = .5 .2/.4 = .5 Constant Geometric

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 ...

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

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

Algebra
-1/3 > -3

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.

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

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

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

math
(a^4b^6)^0 = 1

Algebra
W=√1/LC W^2 = 1/LC LCW^2 = 1 L = 1/CW^2

algebra
Logb(a) = c Log1/5(25) = 2

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

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

math

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

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

ALGEBRA
• 13 in, 84 in, 85 in

Math
(2/5)(3/8) = 6/40

Algebra
(z + 3)(z +15)

stat
9C2(.17)^2(.83)^7

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

statistics 101 college
phat = 8/28 = 0.286

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%

ALGEBRA
1 -15 = 36x -72 -14 +72 =36x 58 =36x 58/36 = x 29/18 = x

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

math
All correct except 5 #5 is d

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

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

economics (4)
(1/.2)* 40 = \$200 billion

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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