A man is walking down a very long flight of
steps in a stairwell. He begins at 136 feet
above ground level. He walks down with a
steady rate such that he gets closer to the
ground floor at a rate of 2.8 feet per second.
The man is going to exit the stairwell at the
4th floor, which is the height of 42 feet above
ground level. Let t be equal to the number of
seconds it takes for him to get to the 4th floor.
Set up and solve the equation to find the value
of t. Round your answer to the nearest tenth
of a second.

Answer:

The environmentalist can be 90% confident that the true mean weight of all cars is between 2.8 and 3.4 tons.

Step-by-step explanation:

x% confidence interval:

A confidence interval is built from a sample, has bounds a and b, and has a confidence level of x%. It means that we are x% confident that the population mean is between a and b.

In this question:

90% confidence interval between 2.8 and 3.4 tons. This means that the environmentalist can be 90% sure that the mean weight of all cars is in this interval, that is:

The environmentalist can be 90% confident that the true mean weight of all cars is between 2.8 and 3.4 tons.

Answer:

There are many outcomes or data that needs to be collected... like does the iPhone and android share the same speaker? or are your speaker grills blocked out by something? or is your iPhone old, because they do change the speaker each gen.

Answer:

I think this is right hope you understand

Answer:

x²+5x-14

Step-by-step explanation:

For this equation, you want to use FOIL (multiply first terms, then outside terms, then inside terms, then last terms) to expand the brackets.

This gives x×x+x×-2+x×7+7×-2, which simplifies to x²-2x+7x-14, and further to x²+5x-14.

**This content involves expanding quadratics with FOIL, which you may wish to revise. I'm always happy to help!

Answer:

Diego can choose the 15 items in 128 different ways.

Step-by-step explanation:

Since at the grocery store, Diego has narrowed down his selections to 4 vegetables, 8 fruits, 6 cheeses, and 4 whole grain breads, and he wants to use the Express Lane, so he can only buy 15 items, to determine how many ways can he choose which 15 items to buy if he wants all 6 cheeses the following calculation must be performed:

4 x 4 x 8 = X

16 x 8 = X

128 = X

Therefore, Diego can choose the 15 items in 128 different ways.

Answer:

76

Step-by-step explanation:

19 out of 50 are in 7th grade.

200/50 = 4

Multiply both numbers in the ratio by 4.

19 out of 50 = 76 out of 200

Answer: 76

The answer is B

the method use to solved this is called foil

Answer:

the answer is 3.5

Step-by-step explanation:

Given:

The number [tex]\sqrt{63}[/tex] lies between two whole numbers.

To find:

The two consecutive whole numbers.

Solution:

The perfect squares of natural numbers are 1, 4, 9, 16, 25, 36, 49, 64, 81, 100, ... .

The number 63 lies between 49 and 64.

[tex]49<63<64[/tex]

Taking square root on each side, we get

[tex]\sqrt{49}<\sqrt{63}<\sqrt{64}[/tex]

[tex]7<\sqrt{63}<8[/tex]

Therefore, the number [tex]\sqrt{63}[/tex] lies between two whole numbers 7 and 8.

Answer:

Step-by-step explanation:

[tex]5u\leq 8u-21[/tex]

Subtract 8u from both sides

[tex]-3u\leq -21[/tex]

Divide by -3 on both sides

[tex]u\geq 7[/tex]

Interval notation: [greater/less than or equal to], (greater or equal to)

[7,∞)

The solution to the inequality is u ≥ 7, which means that u is greater than or equal to 7. In interval notation [ 7, ∞).

In mathematics, an inequality is a remark that two values or expressions are not equal. An inequality uses one of the comparison symbols: "<" (less than), ">" (greater than), "≤" (less than or equal to), "≥" (greater than or equal to), or "≠" (not equal to).

Here,

To solve the inequality 5u ≤ 8u - 21, we can start by isolating u on one side of the inequality. We can do this by subtracting 5u from both sides:

5u ≤ 8u - 21

-3u ≤ -21

Divide both sides by -3. Note that dividing by a negative number will reverse the direction of the inequality:

u ≥ 7

Therefore, the solution to the inequality is u ≥ 7, which means that u is greater than or equal to 7. In interval notation [ 7, ∞).

Learn more about inequality here:

brainly.com/question/14098842

#SPJ2

Answer:

inscribed

Step-by-step explanation:

For any given triangle, the circle inside of it is called the Inscribed circle

Answer:

B

Step-by-step explanation:

Base area = side^2 = 3^2 = 9 m^2

Base perimeter = side x 4 = 3 x 4 = 12 m

LA = (base perimeter x slant height)/2 = (12 x 5)/2 = 30 m

SA = base area + LA = 9 + 30 = 39 m^2

Answer:

- 0.125

Step-by-step explanation:

Given the equation :

(0.020(5/4) + 3 ((1/5) – (1/4)))

0.020(5/4) = 0.025

3((1/5) - (1/4)) = 3(1/5 - 1/4) = 3(-0.05) = - 0.15

0.025 + - 0.15 = 0.025 - 0.15 = - 0.125

Answer:

2 hours

Step-by-step explanation:

10/50 * 10 = 2

Answer:

A

Step-by-step explanation:

You divide distance over time so 200 divided by 8.

Answer:

75

Step-by-step explanation:

Substitute 6 for f

12f+3=

12*6+3=

72 + 3 = 75

Answer:

12f+3 = 75 when f = 6

Step-by-step explanation:

12f+3

Let f = 6

12*6+3

Multiply

72 +3

Add

75

Answer:

Option B. A = (5/6)^-⅛

Step-by-step explanation:

From the question given above, we obtained:

(5/6)ˣ = A¯⁸ˣ

We can obtain the value of A as follow:

(5/6)ˣ = A¯⁸ˣ

Cancel x from both side

5/6 = A¯⁸

Recall:

M¯ⁿ = 1/Mⁿ

A¯⁸ = 1/A⁸

Thus,

5/6 = 1/A⁸

Cross multiply

5 × A⁸ = 6

Divide both side by 5

A⁸ = 6/5

Take the 8th root of both sides

A = ⁸√(6/5)

Recall

ⁿ√M = M^1/n

Thus,

⁸√(6/5) = (6/5)^⅛

Therefore,

A = (6/5)^⅛

Recall:

(A/B)ⁿ = (B/A)¯ⁿ

(6/5)^⅛ = (5/6)^-⅛

Therefore,

A = (5/6)^-⅛

9514 1404 393

Answer:

  B.

Step-by-step explanation:

Use t=0 and t=2 and locate the graph with those two points on it. (We choose these because the horizontal grid is 2 years for each grid line.)

For t=0, C(0) = 50000(0.9^0) -2000 = 480000

For t=2, C(2) = 50000(0.9^2) -2000 = 40500 -2000 = 38500

The only graph that has y-intercept of 48000 and crosses (2, 38500) is the one shown in choice B.

Answer:

0.7888 = 78.88% probability that the first machine produces an acceptable cork.

0.9772 = 97.72% probability that the second machine produces an acceptable cork.

Step-by-step explanation:

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

First machine:

Mean 3 cm and standard deviation 0.08 cm, which means that [tex]\mu = 3, \sigma = 0.08[/tex]

What is the probability that the first machine produces an acceptable cork?

This is the p-value of Z when X = 3.1 subtracted by the p-value of Z when X = 2.9. So

X = 3.1

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{3.1 - 3}{0.08}[/tex]

[tex]Z = 1.25[/tex]

[tex]Z = 1.25[/tex] has a p-value of 0.8944

X = 2.9

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{2.9 - 3}{0.08}[/tex]

[tex]Z = -1.25[/tex]

[tex]Z = -1.25[/tex] has a p-value of 0.1056

0.8944 - 0.1056 = 0.7888

0.7888 = 78.88% probability that the first machine produces an acceptable cork.

What is the probability that the second machine produces an acceptable cork?

For the second machine, [tex]\mu = 3.04, \sigma = 0.03[/tex]. Now to find the probability, same procedure.

X = 3.1

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{3.1 - 3.04}{0.03}[/tex]

[tex]Z = 2[/tex]

[tex]Z = 2[/tex] has a p-value of 0.9772

X = 2.9

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{2.9 - 3.04}{0.03}[/tex]

[tex]Z = -4.67[/tex]

[tex]Z = -4.67[/tex] has a p-value of 0

0.9772 - 0 = 0.9772

0.9772 = 97.72% probability that the second machine produces an acceptable cork.

Answer:

a. μ = 25

b. σ = 16.496

Step-by-step explanation:

Note: See the attached excel for the calculation of Mean and Deviation from Mean.

Let: N = Number of observation = 9

F = Frequency

Therefore, we have:

a. Compute the expected number of arrivals per minute. μ=___( please type as an integer or a decimal)

From the attached excel file, we have:

Total F = 200

Therefore, we have:

μ = Mean = Total of F / (N - 1) = 200 / (9 - 1) = 25

b. Compute the standard deviation σ=___(please round to three decimal places as needed)

From the attached excel file, we have:

Total (F -  μ)^2 = 2,177

σ = Standard deviation = (Total of (F -  μ)^2 / (N - 1))^0.5 = (2,177 / (9 - 1))^0.5 = 16.496

Answer:

A = 6; B = -15

Step-by-step explanation:

To have an infinite number of solutions, both equations must be the same.

4x - Ay = 15

-4x + 6y = B

The only coefficient we see in both equations is the coefficient of the x term. We have -4x and 4x. Multiply both sides of the second equation by -1.

4x - Ay = 15

4x - 6y = -B

For the equation to be equal, we need each term of one equation to be equal to the corresponding term of the other equation.

4x and 4x are equal.

-Ay must equal -6y

-Ay = -6y

-A = -6

A = 6

15 must equal -B

-B = 15

B = -15

Answer: A = 6; B = -15

Answer:

option 2

Step-by-step explanation:

Using trigonometric ratio:

[tex]Cos \ 60 = \frac{adjacent } {hypotenuse} \\\\\frac{1}{2} = \frac{4}{u}\\\\1 \times u = 2 \times 4 \\\\u = 8[/tex]

Now using Pythagoras theorem we will find v

[tex]8^2 = 4^2 + v^2\\\\64 = 16 + v^2\\\\v^2 = 64 - 16 \\\\v = \sqrt{48} = \sqrt{16 \times 3} = \sqrt{4^2 \times 3 } = 4\sqrt{3}[/tex]

By using trigonometric relations, we will see that v = 4*√3 and u = 8

Here we have a right triangle, we can use trigonometric relations to find the missing sides.

We can see that v is the opposite cathetus of the 60° angle, then we can use the relation:

tan(a) = (opposite cathetus)/(adjacent cathetus)

Replacing what we know, we get:

tan(60°) = v/4

4*tan(60°) = v = 4*√3

To get the value of u, we use:

cos(a) = (adjacent cathetus)/(hypotenuse).

cos(60°) = 4/u

u = 4/cos(60°) = 2*4 = 8

Then we have:

v = 4*√3

u = 8

If you want to learn more about triangles, you can read:

https://brainly.com/question/17972372

9514 1404 393

Answer:

  90° CCW

Step-by-step explanation:

The transformation from B to B' is ...

  B(-4, 1) ⇒ B'(-1, -4)

  (x, y) ⇒ (-y, x) . . . . . matches the transformation for 90° CCW

Answer:

90 degrees

Step-by-step explanation:

Answer:

76 sq. meters

Step-by-step explanation:

10 · 4 = 40m

2 · 6 = 12m

8 · 6 = 48/2 = 24m

40 + 12 + 24 = 76 sq. meters

Answer:

(-1.5, 0.5)

Step-by-step explanation:

x = -1.5

y = 0.5

(-1.5, 0.5)

Answer:

angle M = 60

angle Q = 70

Step-by-step explanation:

M 180/3 = 60

Q 180-40 = 140/2 = 70

t-3.2 ≤ 7.5

"at most" means less than or equal to

Answer:

(8x + 1)° + ( 4x+11)° = 180° (linear pair )

8x +1 + 4x +11 = 180

8x + 4x + 1 + 11 = 180

12x + 12 = 180

12x = 180 - 12

12x = 168

x= 168/12

x = 14