coal mines have shafts that can be as much as 7 feet deep. About how many feet deep into earth's crust are these shafts?

Im seriously in need of help anybody im not joking around please!!!!!

marishachu [46]

Answer:

A.) = 6

If RE = 12, then RD = 6

B.) = 10

If BR = 10, then BE = 10

C.) = 16

If BD = 8, then BK = 16

D.) = 30*

<m9 = 90*, and <m2 = 60*, so add them and subtract from 180*, you are left with <m1 = 30*

E.) = 60*

If <m2 = 60*, then <m3 = 60*

F.) = 90*

It`s a 90* angle because BK and RE and perpendicular

G.) = 60*

If <m1 = 30*, then multiply by two because it is symmetrical

I would show all my work but you seem to be in a rush. Hope this helps!

4 0

3 years ago

Identify the vertex, the focus, and the directrix of the parabola with the given equation.

Elenna [48]

Vertex: (-4,-3)
Focus: (-4, -11/4)
Directrix: y= -13/4

7 0

3 years ago

Pat listed all the numbers that have 15 as a multiple. Write the numbers in pats list

tiny-mole [99]

I believe the answer is 1,3,5,15

8 0

4 years ago

Read 2 more answers

Two groups of students order burritos and tacos at a local restaurant. One order of 3 burritos and 4 tacos coast 11.33. The othe

makkiz [27]

3B + 4T = 11.33 9B + 5T = 23.56 Solve by elimination: Multiply the first equation by -3 to get -9B where the 3B is so that it will cancel with the 9B when the equations are added. -9B - 12T = -33.99 9B + 5T = 23.56 ------------------ -7T = -10.43 T = $1.49 Substitute in 3B + 4T = 11.33 3B + 4(1.49) = 11.33 3B + 5.96 = 11.33 3B = 5.37 B = $1.79 A taco costs $1.49 and a burrito costs $1.79. Therefore 5 burritos and 7 tacos will cost 5B + 7T = 5($1.79) + 7($1.49) = $19.38

7 0

3 years ago

Because of safety considerations, in May 2003 the Federal Aviation Administration (FAA) changed its guidelines for how small com

Rasek [7]

Answer:

a) The 95% confidence interval for the mean summer weight (including carry-on luggage) of Frontier Airlines passengers is between 179 and 187 pounds. This means that we are 95% sure that the mean summer weight of all Frontier Airlines passengers is between these two values.

b)

The 95% confidence interval for the mean winter weight (including carry-on luggage) of Frontier Airlines passengers is between 185.4 pounds and 194.6 pounds. This means that we are 95% sure that the mean winter weight of all Frontier Airlines passengers is between these two values.

c) They are respected, as the upper bound of both intervals is below the new FAA recommendations.

Step-by-step explanation:

We have the standard deviation for the sample, which means that the t-distribution is used to solve these questions.

Question a:

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 100 - 1 = 99

95% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 99 degrees of freedom(y-axis) and a confidence level of $1 - \frac{1 - 0.95}{2} = 0.975$ . So we have T = 1.9842

The margin of error is:

$M = T\frac{s}{\sqrt{n}} = 1.9842\frac{20}{\sqrt{100}} = 4$

In which s is the standard deviation of the sample and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 183 - 4 = 179 pounds.

The upper end of the interval is the sample mean added to M. So it is 183 + 4 = 187 pounds.

The 95% confidence interval for the mean summer weight (including carry-on luggage) of Frontier Airlines passengers is between 179 and 187 pounds. This means that we are 95% sure that the mean summer weight of all Frontier Airlines passengers is between these two values.

Question b:

Critical value is the same(same sample size and confidence level).

The margin of error is:

$M = T\frac{s}{\sqrt{n}} = 1.9842\frac{23}{\sqrt{100}} = 4.6$

The lower end of the interval is the sample mean subtracted by M. So it is 190 - 4.6 = 185.4 pounds.

The upper end of the interval is the sample mean added to M. So it is 190 + 4.6 = 194.6 pounds.

The 95% confidence interval for the mean winter weight (including carry-on luggage) of Frontier Airlines passengers is between 185.4 pounds and 194.6 pounds. This means that we are 95% sure that the mean winter weight of all Frontier Airlines passengers is between these two values.

c. The new FAA recommendations are 190 pounds for summer and 195 pounds for winter. Comment on these recommendations in light of the confidence interval estimates from Parts (a) and (b).

They are respected, as the upper bound of both intervals is below the new FAA recommendations.

7 0

3 years ago