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3 years ago

6

A diesel train traveled to Las Vegas and back. The trip there took ten hours and the trip back took 14 hours. It averaged 60 mph

on the return trip. Find the average speed of the trip there.

1 answer:

salantis [7]3 years ago

6 0

The average speed is 4 miles per hour

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using the numbers 5, 8, and 24, create a problem using no more than four operations (addition, subtraction, division, square, sq

irga5000 [103]

24^2 / (8+5)

576 / 13

= 44.3

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3 years ago

Please help me. After charging for 1/3 of an hour, a phone is at 2/5 of its full power. How long will it take the phone to charg

yanalaym [24]

Answer:

D

Step-by-step explanation:

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3 years ago

Statuary Hall is an elliptical room in the United States Capitol in Washington, D.C. The room is also called the Whispering Gall

dalvyx [7]

Answer: a) $\frac{x^{2} }{2352.25 }$ + $\frac{y^{2} }{529}$ = 1

b) The distance of two foci is 85.4 feet

c) Area = 3502.67 square feet

Step-by-step explanation: a) An ellipse has the equation in the form of:

$\frac{x^{2} }{a^{2} }$ + $\frac{y^{2} }{b^{2} }$ = 1, where a is the horizontal axis and b is the vertical axis.

For the Statuary Hall, a = $\frac{97}{2}$ = 48.5 and b = $\frac{46}{2}$ = 23, so the equation will be

$\frac{x^{2} }{2352.25 }$ + $\frac{y^{2} }{529}$ = 1.

b) To determine the distance of the foci, we have to calculate 2c, where c is the distance between one focus and the center of the ellipse. To find c, as a, b and c create a triangle with a as hypotenuse:

$a^{2}$ = $b^{2} + c^{2}$

$c^{2} = a^{2} - b^{2}$

c = $\sqrt{48.5^{2} - 23^{2} }$

c = 42.7

The distance is 2c, so 2·42.7 = 85.4 feet.

The two foci are 85.4 feet apart.

c)The area of an ellipse is given by:

A = a.b.π

A = 48.5 · 23 · 3.14

A = 3502.67 ft²

The area of the floor room is 3502.67ft².

3 0

3 years ago

Instructions: Find the angle measures given the figure is a rhombus.

Oksi-84 [34.3K]

Answer:

Angle ABC =70

Step-by-step explanation:

Divide 140 by 2 and apply the rule of alternante interior angles

8 0

3 years ago

3. Using the sample size of 800 and the proportion 0.47, calculate the margin of error associated with the estimate of the propo

salantis [7]

Answer:

$ME=1.96\sqrt{\frac{0.47 (1-0.47)}{800}}=0.0346$

Step-by-step explanation:

Previous concepts

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 population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{p(1-p)}{n}})$

Solution to the problem

We assume for this case a confidence level of 95%. In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 95% of confidence, our significance level would be given by $\alpha=1-0.95=0.05$ and $\alpha/2 =0.025$ . And the critical value would be given by:

$z_{\alpha/2}=-1.96, z_{1-\alpha/2}=1.96$

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

$\hat p \pm z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

And if we replace the values obtained we got this:

$ME=1.96\sqrt{\frac{0.47 (1-0.47)}{800}}=0.0346$

6 0

3 years ago