# Posts by Kuai

Total # Posts: 994

**Math**

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

*October 30, 2016*

**Math**

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

*October 16, 2015*

**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)

*October 15, 2015*

**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

*June 8, 2014*

**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

*June 3, 2014*

**math pls help!!!!!**

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

*May 31, 2014*

**Statistics 1**

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

*May 30, 2014*

**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?

*May 24, 2014*

**Math**

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

*May 24, 2014*

**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.

*May 23, 2014*

**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

*May 21, 2014*

**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

*May 21, 2014*

**algebra 2**

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

*May 21, 2014*

**Algebra**

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

*May 21, 2014*

**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

*May 21, 2014*

**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]

*May 21, 2014*

**Maths (Integration)**

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

*May 21, 2014*

**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$

*May 21, 2014*

**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

*May 21, 2014*

**math--check my answer**

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

*May 20, 2014*

**statistics**

80 * .2 16

*May 20, 2014*

**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

*May 19, 2014*

**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

*May 19, 2014*

**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

*May 19, 2014*

**Statictics**

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

*May 19, 2014*

**Statistics**

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

*May 19, 2014*

**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

*May 19, 2014*

**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

*May 18, 2014*

**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.

*May 18, 2014*

**statistics**

20/36

*May 18, 2014*

**statistics**

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

*May 18, 2014*

**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

*May 17, 2014*

**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...

*May 17, 2014*

**Algebra**

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

*May 17, 2014*

**Statistics**

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

*May 16, 2014*

**ALGEBRA**

mean = 9.3, median = 10, mode = 13

*May 15, 2014*

**Statistics**

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

*May 14, 2014*

**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

*May 13, 2014*

**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

*May 13, 2014*

**Geometry**

Yes

*May 13, 2014*

**Algebra 1 Answer Evaluation**

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

*May 13, 2014*

**Algebra**

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

*May 13, 2014*

**algebra**

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

*May 13, 2014*

**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

*May 13, 2014*

**Math**

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

*May 13, 2014*

**Math Help**

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

*May 13, 2014*

**Math**

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

*May 12, 2014*

**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

*May 12, 2014*

**Algebra**

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

*May 12, 2014*

**Pre-algebra**

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

*May 12, 2014*

**Math**

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

*May 12, 2014*

**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 ...

*May 11, 2014*

**Economics (42)**

You're welcome.

*May 11, 2014*

**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)

*May 11, 2014*

**Math**

Ok

*May 11, 2014*

**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

*May 11, 2014*

**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

*May 11, 2014*

**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

*May 11, 2014*

**MAth**

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

*May 10, 2014*

**algebra**

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

*May 10, 2014*

**Stats**

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

*May 9, 2014*

**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 ...

*May 9, 2014*

**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)

*May 9, 2014*

**Economics (41)**

I did not know how to do it.

*May 9, 2014*

**Economics (41)**

Only c is correct

*May 9, 2014*

**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 ...

*May 9, 2014*

**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...

*May 9, 2014*

**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...

*May 9, 2014*

**Math**

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

*May 9, 2014*

**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 ...

*May 9, 2014*

**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

*May 9, 2014*

**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

*May 9, 2014*

**Algebra**

-1/3 > -3

*May 8, 2014*

**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.

*May 8, 2014*

**Math**

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

*May 8, 2014*

**math**

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

*May 8, 2014*

**math**

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

*May 8, 2014*

**math**

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

*May 8, 2014*

**Algebra**

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

*May 8, 2014*

**algebra**

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

*May 7, 2014*

**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

*May 7, 2014*

**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

*May 7, 2014*

**math**

Wrong answer

*May 7, 2014*

**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

*May 7, 2014*

**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

*May 7, 2014*

**ALGEBRA**

• 13 in, 84 in, 85 in

*May 7, 2014*

**Math**

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

*May 7, 2014*

**Algebra**

(z + 3)(z +15)

*May 6, 2014*

**stat**

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

*May 6, 2014*

**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

*May 6, 2014*

**statistics 101 college**

phat = 8/28 = 0.286

*May 5, 2014*

**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%

*May 5, 2014*

**ALGEBRA**

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

*May 5, 2014*

**math**

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

*May 2, 2014*

**math**

All correct except 5 #5 is d

*May 2, 2014*

**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

*May 1, 2014*

**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

*May 1, 2014*

**economics (4)**

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

*May 1, 2014*

**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) + ...

*May 1, 2014*