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1 year ago

8

The number of concert tickets sold doubles every hour. After 12 hours, all of the tickets are sold. After how many hours are abo

ut one-fourth of the tickets sold. Explain your reasoning.

1 answer:

olga nikolaevna [1]1 year ago

6 0

About 3. 3x4= 12, but the number of concert tickets doubles, so after about 3-4 it should be 1/4 tickets sold.

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Find the area of the part of the plane 5x + 4y + z = 20 that lies in the first octant.

BlackZzzverrR [31]

This part of the plane is a triangle. Call it $\mathcal S$ . We can find the intercepts by setting two variables to 0 simultaneously; we'd find, for instance, that $y=z=0$ means $5x=20\implies x=4$ , so that (4, 0, 0) is one vertex of the triangle. Similarly, we'd find that (0, 5, 0) and (0, 0, 20) are the other two vertices.

Next, we can parameterize the surface by

$\mathbf s(u,v)=\langle4(1-u)(1-v),5u(1-v),20v\rangle$

so that the surface element is

$\mathrm dS=\|\mathbf s_u\times\mathbf s_v\|=20\sqrt{42}(1-v)\,\mathrm du\,\mathrm dv$

Then the area of $\mathcal S$ is given by the surface integral

$\displaystyle\iint_{\mathcal S}\mathrm dS=20\sqrt{42}\int_{u=0}^{u=1}\int_{v=0}^{v=1}(1-v)\,\mathrm dv\,\mathrm du$
$\displaystyle=20\sqrt{42}\int_{v=0}^{v=1}(1-v)\,\mathrm dv=10\sqrt{42}\approx64.8074$

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2 years ago

Amy hiked 3.25 miles farther than Meng. Amy hiked 7 miles. Which equation can be used to find the number of miles, x, Meng hiked

Verdich [7]

Let distance covered by Meng be 'x' (given)

x+3.25=7

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2 years ago

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How do you find parametric equation for line with slope -2, passing through the point P(-10, -20)?

olga_2 [115]

Y=-2x-40 will be equation

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2 years ago

En una fábrica de automóviles que trabaja las 24 horas se arman diariamente 24

saul85 [17]

Answer:

a. La ganancia es de $ 4,060,000.00

b. 31 vehículos

Step-by-step explanation:

(a) Los parámetros dados son;

El número de automóviles tipo sedán fabricados = 24

El número de camiones tipo SUV fabricados = 16

El número de camiones tipo VAN fabricados = 12

El número de camionetas pick-up fabricadas = 8

El número de autos deportivos fabricados = 2

La ganancia por la venta de autos tipo sedán = $ 185,000 - $ 140,000 = $ 40,000

La ganancia por la venta de camionetas tipo SUV = $ 320,000 - $ 250,000 = $ 70,000

La ganancia por la venta de camiones tipo VAN = $ 400,000 - $ 310,000 = $ 90,000

La ganancia por la venta de las camionetas pick-up = $ 285,000 - $ 210,000 = $ 75,000

La ganancia por la venta de los autos deportivos = $ 550,000 - $ 400,000 = $ 150,000

La ganancia = 24 * $ 40 000 + 16 * $ 70 000 + 12 * $ 90 000 + 8 * $ 75 000 + 2 * $ 150 000 = $ 4060 000

(b) Por lo que hay una tasa de producción constante, solo la mitad de los automóviles se producirán dentro del período de 12 horas

Por lo tanto, tu fabricado

12 autos sedán, 8 camionetas tipo SUV, 6 camionetas tipo VAN, 4 camionetas pick-up y 1 auto deportivo para hacer un total de 31 vehículos.

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2 years ago

The manufacturer of hardness testing equipment uses steel-ball indenters to penetrate metal that is being tested, however, the m

masha68 [24]

Answer:

$1.667-2.31\frac{1.803}{\sqrt{9}}=0.2789$

$1.667+2.31\frac{1.803}{\sqrt{9}}=3.055$

So on this case the 95% confidence interval would be given by (0.2789;3.055)

The 95% confidence interval to judge whether the two indeners result in different measurements is?

Yes the confidence interval not contains the value 0 so we can conclude that the values for Diamond are significantly higher than the values for Steel Ball at 5% of significance.

Step-by-step explanation:

We have the following dataset:

specimen 1 2 3 4 5 6 7 8 9

Steel Ball 51 57 61 70 68 54 65 51 53

Diamond 53 55 63 74 69 56 68 51 56

If we calculate the differences diamond-steel ball we have this datase:

d: 2, -2, 2, 4, 1, 2, 3, 0, 3

The second step is calculate the mean difference

$\bar d= \frac{\sum_{i=1}^n d_i}{n}=1.667$

The third step would be calculate the standard deviation for the differences, and we got:

$s_d =\frac{\sum_{i=1}^n (d_i -\bar d)^2}{n-1} =1.803$

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n-1=9-1=8$

Since the confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,9)".And we see that $t_{\alpha/2}=2.31$ .

Now we have everything in order to replace into formula (1):

$1.667-2.31\frac{1.803}{\sqrt{9}}=0.2789$

$1.667+2.31\frac{1.803}{\sqrt{9}}=3.055$

So on this case the 95% confidence interval would be given by (0.2789;3.055)

The 95% confidence interval to judge whether the two indeners result in different measurements is?

Yes the confidence interval not contains the value 0 so we can conclude that the values for Diamond are significantly higher than the values for Steel Ball at 5% of significance.

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2 years ago