4 people can dig a trench in 3 hours.
How long would it take 9 people?
Give your answer in minutes.

Step-by-step explanation:

-√81=-√(9)²=-9

A number inside a Square root cannot ne negative. So, the second one is not a real no.

Answer:

[tex] - \sqrt{81} = - 9 \\ \sqrt{ - 25 = - 5} [/tex]

Step-by-step explanation:

-81/9 9+9+9+9+9+9+9+9+9(81)

-9

-25/5 (5+5+5+5+5(25)

-5

a) The horizontal distance between the fighter jet and the point of impact of the missile is 100 units.

b) The graph of the equation is a downward-opening parabola passing through the points (50, 22500), (100, 0), and (0, 0).

c) The instantaneous rate of change when the missile has half of the horizontal journey left is 0, indicating no change in height with respect to the horizontal distance at that point.

To find the horizontal distance between the fighter jet and the point of impact of the missile, we need to determine the x-coordinate when the missile hits the ground. This can be done by finding the x-intercepts of the equation -x² + 100x + 20000, which represents the path of the missile.

To find the x-intercepts, we set the equation equal to zero:

-x² + 100x + 20000 = 0

Using the quadratic formula, where a = -1, b = 100, and c = 20000, we can calculate the x-coordinate:

x = (-b ± √(b² - 4ac)) / (2a)

Plugging in the values, we get:

x = (-100 ± √(100² - 4(-1)(20000))) / (2(-1))

Simplifying further:

x = (-100 ± √(10000 + 80000)) / (-2)

x = (-100 ± √90000) / (-2)

x = (-100 ± 300) / (-2)

x = (200 or -100) / 2

Since negative values are not meaningful in this context, we take the positive value, which is x = 100. Therefore, the horizontal distance between the fighter jet and the point of impact of the missile is 100 units.

To graph the equation, we plot the points on a coordinate system. The equation -x² + 100x + 20000 represents a downward-opening parabola. The highest point of the parabola is at (50, 22500) because the x-coordinate represents the midpoint of the parabolic path, and the maximum height is reached when x = 50. The two ends of the parabolic path are located at the x-intercepts we calculated earlier, which are (100, 0) and (0, 0).

The graph of the equation would show a downward-opening parabola passing through the points (50, 22500), (100, 0), and (0, 0).

The instantaneous rate of change represents the derivative of the equation with respect to x at a given point. To find the instantaneous rate of change when the missile has half of the horizontal journey left, we need to find the derivative of the equation and evaluate it at that point.

Taking the derivative of -x² + 100x + 20000 with respect to x, we get -2x + 100. Evaluating this derivative at x = 50 (when the missile has half of the horizontal journey left), we have:

-2(50) + 100 = -100 + 100 = 0

Therefore, the instantaneous rate of change when the missile has half of the horizontal journey left is 0. This indicates that at that point, the height of the missile is not changing with respect to the horizontal distance.

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The expressions that are not written correctly in scientific notation are: 48,200, 36.105, 8.7.10-1, and 0.78.10-3

Scientific notation is a way to express numbers in a concise form, using a number between 1 and 10 multiplied by a power of 10. Let's analyze the given expressions and identify the ones that are not written correctly in scientific notation:

48,200: This expression is not written in scientific notation. It should be expressed as 4.82 × 10^4 or 4.82e4.

0.00099: This expression is correctly written in scientific notation. It can be expressed as 9.9 × 10^-4 or 9.9e-4.

36.105: This expression is not written in scientific notation. It should be expressed as 3.6105 × 10^1 or 3.6105e1.

8.7.10-1: This expression is not written correctly in scientific notation. Scientific notation only allows one decimal point in the number. The correct representation would be 8.7 × 10^-1 or 8.7e-1.

0.78.10-3: Similar to the previous expression, this is not written correctly in scientific notation. The correct representation would be 7.8 × 10^-3 or 7.8e-3.

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Answer:

It would be in thE 20.75

Step-by-step explanation:

Just keep adding change by 9 6 times

d. "Start with a normal approximation as most variables are normal" is least likely to be primary means of investigating normality in a distribution X.

a.  Graphically plot the data in a histogram and use the eyeball test to check for asymmetry or skew. This method involves visually examining the shape of the distribution by creating a histogram. Any noticeable asymmetry or skewness can indicate non-normality.

b. Observe a computerized output for the Q-Q plot of the distribution. A Q-Q plot compares the quantiles of the observed data with the quantiles of a theoretical distribution, such as the normal distribution. If the points on the Q-Q plot closely follow a straight line, it suggests the data is normally distributed.

c. Calculate the observed and expected z-score values and determine any major deviations. By transforming the data into z-scores and comparing them to the expected values under a normal distribution, deviations from normality can be identified. Significant deviations indicate departures from normality.

d. Start with a normal approximation as most variables are normal. This option suggests assuming normality without conducting specific tests or employing appropriate techniques to assess normality. While this approach may be reasonable in certain cases based on prior knowledge or theoretical considerations, it lacks a direct means of investigating normality.

d. "Start with a normal approximation as most variables are normal" is least likely to be primary means of investigating normality in a distribution X.

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Answer:

49.85%

Step-by-step explanation:

Streaming is defined as sending and receiving an video or an audio content in continuous flow over any network. It allows one to begin the playback and while it sends the rest of the data.

In the context, the percentage of the videos on a streaming site that is between 264 and 489 seconds is 49.85% which is found by a graph where the distribution of the lengths of the videos in seconds on a popular video streaming sites.

No, the set of all real-valued functions f(x) such that f(2) = 0 is not a subspace of the vector space consisting of all real-valued functions. The solution set of a nonhomogeneous linear system Ax = b, with b ≠ 0, is also not a subspace of R.

To determine if a set is a subspace, it must satisfy three conditions: closure under addition, closure under scalar multiplication, and contain the zero vector. In the case of the set of real-valued functions f(x) such that f(2) = 0, it fails to satisfy closure under scalar multiplication. If we take a scalar k and multiply it with a function f(x) in the set, the resulting function kf(x) will not necessarily have f(2) = 0. Therefore, the set does not form a subspace.

For the solution set of a nonhomogeneous linear system Ax = b, where b ≠ 0, it also fails to be a subspace of R. A subspace must contain the zero vector, which corresponds to the homogeneous solution of the linear system. However, in a nonhomogeneous system, the zero vector is not a valid solution since Ax ≠ b. Therefore, the set of solutions does not contain the zero vector and cannot be considered a subspace.

In conclusion, neither the set of real-valued functions with f(2) = 0 nor the solution set of a nonhomogeneous linear system with b ≠ 0 form subspaces in their respective vector spaces.

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(a) To show that v(x, y) is an ideal flow, we need to verify that it satisfies the conditions of being both irrotational and incompressible.

For irrotationality, we compute the curl of v(x, y):

curl(v) = ∂v_y/∂x - ∂v_x/∂y = 0 - 0 = 0

Since the curl is zero, v(x, y) is irrotational.

For incompressibility, we compute the divergence of v(x, y):

div(v) = ∂v_x/∂x + ∂v_y/∂y = 2 - 0 = 2

Since the divergence is not zero, v(x, y) is not incompressible. Therefore, v(x, y) is an irrotational flow but not an ideal flow.

(b) For the complex potential Φ for v(x, y), we can integrate the components of v(x, y) with respect to z = x + iy.

Φ = ∫ (2) dz = 2z = 2(x + iy) = 2x + 2iy

The complex potential Φ is given by Φ = 2x + 2iy.

(c) we need to solve for the points where both components of v are zero simultaneously:

v_x = 2x = 0

v_y = 0

From the first equation, x = 0. Substituting x = 0 into the second equation, we get v_y = 0, which holds for all values of y. Therefore, the stagnation point(s) of v(x, y) is at x = 0, y = y.

(d) For the streamlines (trajectories) of v, we can solve the differential equation given by dw/dz = Su_x - iu_y, where w is the complex potential Φ.

dw/dz = ∂Φ/∂x - i∂Φ/∂y = 2 - 2i

Integrating the above expression with respect to z, we get:

w = 2z - 2iz = 2(x + iy) - 2i(x + iy) = 2x + 2iy - 2ix - 2y = 2(x - y) + 2i(y - x)

The streamlines are given by the equation w = 2(x - y) + 2i(y - x), which shows that v(x, y) is a tangent vector to the streamline at z = x + iy (excluding the stagnation point(s)).

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The interval 12.3 < p < 31.2 is a 98% confidence interval for the widget width, indicating that we can be 98% confident that the true population mean falls within this range based on the student's sample data of size n = 21.

The interval 12.3 < p < 31.2 is a 98% confidence interval for the widget width based on the student's sample of size n = 21.

Interpreting this confidence interval means that we can be 98% confident that the true population parameter, the mean widget width (p), falls between 12.3 and 31.2.

This confidence level suggests that if we were to take multiple random samples and calculate confidence intervals using the same method, approximately 98% of those intervals would capture the true population mean.

In other words, the student's sample data suggests that the true widget width has a high likelihood of falling within the range of 12.3 to 31.2 units.

However, it's important to note that this interpretation does not guarantee that the true value of the widget width is within this interval.

It simply provides a range of plausible values based on the sample data and the chosen confidence level.

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Answer:

What is it, you need help with?

Step-by-step explanation:

:)

Answer:

Part A

The two figures, ΔABC and ΔPQR are congruent by the SSS rule of congruency

Part B

The rigid motion that maps ΔABC to ΔPQR are a 180° clockwise rotation about the origin, followed by a horizontal shift of 1 unit to the right

Step-by-step explanation:

Part A

The given coordinates of the vertices of triangle ABC are;

A(-8, -2), B(-3, -6), C(-2, -2)

The length of side AB = √((-6 - (-2))² + (-3 - (-8))²) = √41

The length of side AC = √((-2 - (-2))² + (-2 - (-8))²) = 6

The length of side BC = √((-6 - (-2))² + (-3 - (-2))²) = √17

The given coordinates of the vertices of triangle PQR are;

P(9, 2), Q(4, 6), R(3, 2)

The length of side PQ = √((6 - 2)² + (4 - 9)²) = √41

The length of side PR = √((2 - 2)² + (3 - 9)²) = 6

The length of side RQ = √((6 - 2)² + (4 - 3)²) = √17

Given that the length of the three sides of triangle ABC are equal to the lengths of the three sides of triangle PQR, we have;

ΔABC ≅ ΔPQR by Side Side Side rule of congruency

Part B

Whereby AB and PQ, and BC and RQ are pair of corresponding sides, the rigid motion that maps ΔABC to ΔPQR are;

1) A 180° clockwise (or counterclockwise) rotation about the origin followed by

2) A shift of 1 unit to the right.

Answer:

One on the left = -1

One on the right = 1/3

Step-by-step explanation:

[tex]slope=\frac{rise}{run}[/tex]

One on the left = [tex]\frac{-3}{3} =-1[/tex]

One on the right = [tex]\frac{1}{3} =\frac{1}{3}[/tex]

The gradient of the first line and the second line will be 1 and 1/3, respectively.

The slope is the ratio of rising or falling and running. The difference between the ordinate is called rise or fall and the difference between the abscissa is called run.

The slope of the line is given as,

m = (y₂ - y₁) / (x₂ - x₁)

The gradient of the first line is given as,

m = 3 / 3

m = 1

The gradient of the second line is given as,

m = 1 / 3

The gradient of the first line and the second line will be 1 and 1/3, respectively.

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To calculate the percent change from phytoplankton to smelt, you would first need to find the difference between the two concentrations. Then, you would divide the difference by the original concentration and multiply by 100%.

For example, if the concentration of phytoplankton is 100 parts per million (ppm) and the concentration of smelt is 150 ppm, then the difference between the two concentrations is 50 ppm.

Dividing 50 ppm by 100 ppm and multiplying by 100% gives us a percent change of 50%. This means that the concentration of PCBs in smelt is 50% higher than the concentration of PCBs in phytoplankton.

To calculate the percent change from phytoplankton to smelt, you can use the following formula:

Percent change = [tex]\frac{(new value - old value)}{old value } *100%[/tex]

In this case, the new value is the concentration of PCBs in smelt and the old value is the concentration of PCBs in phytoplankton.

Once you have calculated the percent change, you can interpret it by comparing it to a reference value. For example, a percent change of 50% is considered to be a large change. This means that the concentration of PCBs in smelt is much higher than the concentration of PCBs in phytoplankton.

It is important to note that the percent change is only a measure of the relative change between two values. It does not take into account the absolute values of the two values. For example, a percent change of 50% is the same whether the original value is 100 or 1000.

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The sequence an = 5, an+1 = an + 8, a > 1 is an example of a recursively-defined arithmetic sequence. It does not fit the definitions of a geometric sequence, factorial sequence, or Fibonacci-like sequence. The correct option is (d) a recursively-defined arithmetic sequence.

An arithmetic sequence is characterized by a common difference between consecutive terms. In this case, each term (an+1) is obtained by adding a constant value of 8 to the previous term (an).

This satisfies the definition of an arithmetic sequence.

While the sequence does not fit the definition of a geometric sequence, factorial sequence, or Fibonacci-like sequence, it does follow the pattern of an arithmetic sequence.

The terms increase by a constant value of 8 with each step, making it a recursively-defined arithmetic sequence.

Therefore, the correct option is (d) a recursively-defined arithmetic sequence.

Note: A geometric sequence would have a common ratio between consecutive terms, which is not the case here. The factorial sequence involves multiplying terms by consecutive positive integers, and a Fibonacci-like sequence follows the pattern of adding the previous two terms to obtain the next term.

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Null Hypothesis (H0): There is no positive correlation between the rankings of TV shows by husbands and wives in married couples.

Alternative Hypothesis (HA): There is a positive correlation between the rankings of TV shows by husbands and wives in married couples.

In simpler terms, the null hypothesis suggests that there is no relationship or association between the rankings of TV shows by husbands and wives.

The alternative hypothesis, on the other hand, proposes that there is a positive correlation between the rankings, indicating that husbands and wives tend to have similar preferences when it comes to TV shows.

The competing hypotheses in this study aim to determine whether there is evidence to support the idea that husbands and wives tend to like the same TV shows.

The null hypothesis assumes that there is no correlation between the rankings, meaning that the preferences of husbands and wives are independent of each other.

The alternative hypothesis, in contrast, suggests that there is a positive correlation, indicating a tendency for spouses to have similar preferences for TV shows.

To test these hypotheses, the researchers used the Spearman rank correlation coefficient (rs) to quantify the strength and direction of the relationship between the rankings.

The Spearman rank correlation is a statistical measure that assesses the monotonic relationship between two ranked variables, in this case, the rankings of TV shows by husbands and wives. A value of rs = 0.47 indicates a moderate positive correlation between the rankings.

To evaluate the hypotheses, statistical tests can be conducted. The significance level (alpha) is typically set in advance (e.g., 0.05) to determine the threshold for accepting or rejecting the null hypothesis.

If the p-value associated with the test is less than the chosen significance level, the null hypothesis is rejected in favor of the alternative hypothesis, suggesting that there is evidence of a positive correlation between the rankings of TV shows by husbands and wives.

Conversely, if the p-value is greater than the significance level, there is insufficient evidence to reject the null hypothesis, and the data does not provide support for a positive correlation.

It is important to note that the interpretation of the Spearman rank correlation coefficient and the conclusions drawn from the study should consider other factors, such as the sample size, sampling method, and the specific characteristics of the TV shows ranked by the couples.

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Answer:

18ft

Step-by-step explanation:

15+3=18

Answer:

n=1/8N^2

Step-by-step explanation:

n^2-8n=0

-8n=-N^2

n=1/8N^2

Answer:

acceleration

Step-by-step explanation:

use POE:

the object is moving because the graph is not a straight line

the object is not slowing down because the graph is going up

there is not a constant speed because the line is exponential not linear

the only one left is a. acceleration

Answer: (1,2)

Step-by-step explanation:

-2+3=1 and 4-2=2

(1,2)

Answer: $4.20

Step-by-step explanation:

24(.075)=1.80

24+1.80=25.80

30-25.80=4.20

Answer:

The answer is 10.

Step-by-step explanation:

4 + 7 x 2 - 8.

7 x 2 = 14

4 + 14 = 18

18 - 8 = 10

So, the answer is 10

Hope this helps! :)

Using the BODMAS rule, the value of the expression  (4+7x2 –8) is 10.

BODMAS is a system that decides the preference of mathematical operations to solve an expression.

B stands for Bracket

O stands for of

D stands for division

M stands for multiplication

A stands for addition

S stands for subtraction.

So,  In the given expression (4 + 7 x 2 – 8) first, we will do multiplication

i.e. 4+14-8

Secondly, we will do the addition

i.e. 18-8

Lastly, we will subtract

10

Hence, using the BODMAS rule, the value of the expression  (4+7x2 –8) is 10.

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square

its the middle bit that looks darker than the rest.

The solution of the initial value problem is:[tex]Y(t) = e^(3t) + e^(-t) - 3tet[/tex]

To solve the initial value problem Y" – 2y – 3y = 15tet, y(0) = 2, y'(0) = 0, we can use the method of undetermined coefficients.

First, we find the general solution of the homogeneous equation Y" – 2y – 3y = 0.

The characteristic equation is:

[tex]r^2 - 2r - 3 = 0[/tex]

Factoring the quadratic equation, we have:

(r - 3)(r + 1) = 0

This gives us two distinct roots: r = 3 and r = -1.

Therefore, the general solution of the homogeneous equation is:

[tex]Yh(t) = C1e^(3t) + C2e^(-t)[/tex]

To find a particular solution Yp(t) for the non-homogeneous equation, we assume a solution of the form Yp(t) = Atet, where A is a constant to be determined.

Taking the first and second derivatives of Yp(t), we have:

[tex]Yp'(t) = Ate^t + Aet[/tex]

[tex]Yp"(t) = Ate^t + 2Aet[/tex]

Substituting these derivatives into the non-homogeneous equation, we get:

[tex](Ate^t + 2Aet) - 2(Atet) - 3(Atet) = 15tet[/tex]

Simplifying the equation, we have:

[tex]Ate^t + 2Aet - 2Ate^t - 3Ate^t = 15tet[/tex]

Combining like terms, we get:

[tex](-4A + 2A - 3A)te^t = 15tet[/tex]

Simplifying further, we have:

[tex]-5Ate^t = 15tet[/tex]

Cancelling out the common terms, we get:

-5A = 15

Solving for A, we find:

A = -3

Now, we have the particular solution Yp(t) = -3tet.

The general solution of the non-homogeneous equation is the sum of the general solution of the homogeneous equation and the particular solution:

Y(t) = Yh(t) + Yp(t)

[tex]Y(t) = C1e^(3t) + C2e^(-t) - 3tet[/tex]

Using the initial conditions y(0) = 2 and y'(0) = 0, we can solve for the values of C1 and C2.

When t = 0:

[tex]Y(0) = C1e^(3(0)) + C2e^(-0) - 3(0)e^(0)[/tex]

2 = C1 + C2

Taking the derivative of Y(t) with respect to t and evaluating it at t = 0:

[tex]Y'(t) = 3C1e^(3t) - C2e^(-t) - 3te^(3t)Y'(0) = 3C1e^(3(0)) - C2e^(-0) - 3(0)e^(3(0))[/tex]

0 = 3C1 - C2

Solving these equations simultaneously, we find C1 = 1 and C2 = 1.

Therefore, the solution of the initial value problem is:

[tex]Y(t) = e^(3t) + e^(-t) - 3tet[/tex]

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Answer:

Option A

Step-by-step explanation:

To find all missing sides of a right triangle we use the sine, cosine or tangent ratio as below,

sinθ = [tex]\frac{\text{Opposite side}}{\text{Hypotenuse}}[/tex]

cosθ = [tex]\frac{\text{Adjacent side}}{\text{Hypotenuse}}[/tex]

tanθ = [tex]\frac{\text{Opposite side}}{\text{Adjacent side}}[/tex]

Now we take an angle measuring 60°

sin(60°) = [tex]\frac{6}{y}[/tex]

[tex]\frac{\sqrt{3} }{2}=\frac{6}{y}[/tex]

y = 4√3

tan(60°) = [tex]\frac{6}{x}[/tex]

√3 = [tex]\frac{6}{x}[/tex]

x = 2√3

Therefore, Option A will be the correct option.

33. The box plots have been used successfully to describe the center and spread of a data set, the extent and nature of any departure from symmetry and the identification of "outliers".

Hence, the correct option is (d) All of the choices.

34. We can say with a 95% degree of confidence that the mean compressive strength between 3235 and 3265, the correct option is (c) 95%.

Box plots are an excellent way of representing data, which has a statistical measure like variance, median, mean, mode, etc.

It presents the central tendency, variability, skewness, and even show the outliers.

A box plot, also called a box and whisker plot, shows the five-number summary of a set of data (minimum value, lower quartile, median, upper quartile, maximum value).

34. The given information is

Sample size, n = 10

Mean = 3250

Variance = 1000(psi)²

Standard Deviation = √1000(psi)²

= 31.62 psi

The degree of freedom is calculated as follows:

d. f . = n - 1

= 10 - 1

= 9

At 95% confidence level, the area in each tail is given by

α/2 = 0.05/2

= 0.025

Using the t-table, we can find that the t-value for 9 degrees of freedom and 0.025 area in each tail is 2.262.

Therefore, the critical values of t are

t₁ = -2.262 and

t₂ = 2.262.

We can calculate the confidence interval as follows:

Confidence Interval, CI = x± (t × σ/√n)

Plugging in the values, we get

CI = 3250 ± (2.262 × 31.62/√10)

= (3235, 3265)

Hence, we can say with a 95% degree of confidence that the mean compressive strength between 3235 and 3265.

The correct option is (c) 95%.

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