HI, i am in 7th grade i really need help this question is confusing
At the start, the water level of the river was 12 centimeters below its normal water level.
After a day of rain, the water level of the river increased by 18 centimeters.
The next 8 days were dry, and the water level of the river dropped by 2.6 centimeters each day.
Enter a numerical expression representing the water level after the 9 -day period.

What is the value of the expression you entered in part A?
What does the value in part B mean in the situation?

The lower and the upper limit for a 99% confidence interval would be approximately 37.51 and 50.03

Here,

Mean = 43.77

Standard deviation (s)= 12.43655

n= 30

So,

   CI= mean ± t (s/√n)

      = 43.77±2.756(12.43655/√30)

      = 43.77±6.26

      = 37.51,50.03

So, the lower and upper limit would be 37.51 and 50.03

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If the two expression be 14 - 3a and 7a - 9 then the combined term exists 4a + 5.

A mathematical expression is a phrase that has a minimum of two numbers or variables and at least one mathematical operation. It is possible to multiply, divide, add, or subtract in math. An expression has the following structure: Expression: (Math Operator, Number/Variable, Math Operator).

The addition, subtraction, multiplication, and division mathematical operations are used to create mathematical expressions.

Let the two expression be 14 - 3a and 7a - 9

Expression one - 14 - 3a

Expression two - 7a - 9

Combining both two terms

14 - 3a + (7a - 9)  = 14 - 3a + 7a - 9

simplifying the above equation, we get

= (-3a + 7a) + 114 - 9)

=  4a + 5

If the two expression be 14 - 3a and 7a - 9 then the combined term exists 4a + 5.

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Answer:

Wdym what to put for 1 and 2??

Step-by-step explanation:

there’s no picture on my screen ;-;

Answer:

x = 4.083

Step-by-step explanation:

6(2x+5)+19=0

12x+30+19=0

12x+49=0

12x=-49

x=4.083

Answer:

f(2x + 5) = 6x + 19

= 6(2x + 5) + 19

= 12x + 30 + 19

= 12x + 49

f(2) = 12x + 49

= 12(2) + 49

= 73

Step-by-step explanation:

Answer:

C

Step-by-step explanation:

[tex]\frac{6y }{x^{8} } . \frac{4y}{x^{14} }\\\\\frac{24y^{2} }{x^{8+14} } \\\\\frac{24y^{2} }{x^{22} }[/tex]

Answer: 6.4 miles

Step-by-step explanation:

Take 30 divided by 4 = 1 mile every 7.5 minutes

Then take 48 divided by 7.5 = 6.4 miles in 48 minutes

The correct statements are:

1) Leena consumed 1,500 calories at dinner.

2) The equation  2/3(x + 400 + 350) = x

In this question we have been given Leena consumes 400 calories at breakfast and 350 calories at lunch. she consumes 2/3 of her daily calories at dinner.

We need to select a statement that describes the situation  if x represents the calories consumed at dinner.

Let x be the calories consumed at dinner.

Leena consumes 400 calories at breakfast and 350 calories at lunch.

So, the daily calories consumed by her:

400 + 350 + x

Given that she consumes 2/3 of her daily calories at dinner.

From given conditions we get an equation,

x = 2/3(x + 400 + 350)

3x = 2(x + 750)                          ............(multiply both sides by 3)

3x = 2x + 1500                

3x - 2x = 2x + 1500 - 2x            ...............(subtract 2x from both sides)

x = 1500 calories

Therefore, Leena consumed 1500 calories at dinner.

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Answer:

answer on the picture..........

Answer:

4) (5, -1)

Step-by-step explanation:

To find the midpoint, we must average the x coordinates to find the x-coordinate of the midpoint and average the y-coordinates to find the y-coordinate of the midpoint.

Thus, we do:

x-coordinate: [tex]\frac{2 + 8}{2}[/tex] = [tex]\frac{10}{2}[/tex] = [tex]5[/tex]

y-coordinate: [tex]\frac{-5 + 3}{2}[/tex] = [tex]\frac{-2}{2}[/tex] = [tex]-1[/tex]

This means the midpoint has an x-coordinate of 5 and a y-coordinate of -1. This can be expressed as the point (5, -1), which is option 4

As per the concept of unitary method, the another way to express 8 feet is 2 [tex]\frac{2}{3}[/tex] yards.

In math, unitary method is known as a way of finding out the solution of a problem by initially finding out the value of a single unit, and then finding out the essential value by multiplying the single unit value.

Here we have given that a clothesline rope is 8 feet long.

Now we need to find another way to express 8 feet

We know that the formula to convert the measurement it to divide the length by the conversion ratio.

As we know that one yard is equal to 3 feet, then we can use this simple formula to convert is written as

yards = [tex]\frac{feet}{3}[/tex]

Then we have to convert the improper fraction into mixed fraction from, then we get,

2[tex]\frac{2}{3}[/tex] yards

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Answer:3.3

Step-by-step explanation:

Answer:

Step-by-step explanation:

Given angles of elevation of 10° and 50° measured 10 seconds apart from an observation point 1.5 miles away, you want to know the vertical change in distance, and the average speed of the shuttle between the two observations.

The tangent relation tells you ...

  Tan = Opposite/Adjacent

Then the height of the shuttle at the observed angles was ...

  Opposite = Tan · Adjacent

  h1 = tan(10°)·(1.5 mi) ≈ 0.264490 mi

  h2 = tan(50°)·(1.5 mi) ≈ 1.787630 mi

The amount of vertical travel in the 10-second interval was ...

  1.787630 mi -0.264490 mi = 1.523240 mi

The space shuttle traveled about 1.523 miles vertically in the 10-second interval.

In miles per second, the average speed during that time was about ...

  (1.523 mi)/(10 s) = 0.1523 mi/s

In miles per hour, that's about ...

  (0.1523 mi/s)(3600 s/h) ≈ 548 mi/h

the null hypothesis is rejected for an observed p-value of at 0.07 at a significance level of 0.05.

At a significance level of 0.05, the p-value of 0.07 indicates that the observed value is not statistically significant. As a result, the null hypothesis cannot be disproven.In other words, the observed value is not strong enough to prove that the null hypothesis is false. Therefore, the null hypothesis is not rejected for an observed p-value of 0.07 at the significance level of 0.05.

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A coordinate system is a two-dimensional number line, for example, two perpendicular number lines or axes.

This is a typical coordinate system:

coordinate plane1

The horizontal axis is called the x-axis and the vertical axis is called the y-axis.

The center of the coordinate system is called the origin. The axes intersect when both x and y are zero. The coordinates of the origin are (0, 0).

An ordered pair contains the coordinates of one point in the coordinate system. That is named by its ordered pair of the form of (x, y).

The first number corresponds to the x-coordinate and the second to the y-coordinate.

To graph a point, we have to draw a dot at the coordinates that correspond to the ordered pair. It is one of the best ways to start at the origin.

The x-coordinate shows how many steps have to take from positive to negative on the x-axis, the same as the y-coordinate tells how to have many steps from positive to negative on the y-axis.

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A circle of radius 4.6 cm is drawn with its center at the origin. The diameter XY of the circle is also drawn, along with two chords XP and YQ connecting the endpoints of the diameter.

A circle of radius 4.6 cm is drawn with its center at the origin, which is labeled as O. The diameter XY of the circle is also drawn and labeled, with the endpoints X and Y. Two chords XP and YQ are then drawn connecting the endpoints of the diameter. The chord XP starts at X and ends at P, while the chord YQ starts at Y and ends at Q. This diagram demonstrates the idea of a circle and its diameter, as well as how two chords can be drawn from the same two endpoints of a diameter. The circle and its diameter can also be used to calculate the circumference of the circle and the length of the diameter.

Circumference of circle = 2 * π * 4.6 = 28.96 cm

Length of diameter = 2 * 4.6 = 9.2 cm

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The formula used to gain information about an individual data value when the variable is normally distributed is called the z-score formula.

It is used to calculate how many standard deviations a value lies above or below the mean of the data set. The formula is:

z-score = (x - μ) / σ

where x is the data value, μ is the mean of the data set, and σ is the standard deviation of the data set.

To find the z-score of an individual data value when the variable is normally distributed, use the z-score formula. This formula subtracts the mean (μ) from the data value (x) and divides by the standard deviation (σ). This calculation will give you the number of standard deviations the data value lies above or below the mean.

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In an effort to reduce wait times in the emergency room. Eighty patients were polled at random by the investigating committee. And, the upper-bound 95% confidence interval is found to be 1.64.

For small sample numbers or unidentified changes, the t-distribution is used in statistics to calculate the significance of population parameters.

Given sample mean [tex]\overline{X}[/tex] is 1.5 hours, sample size n is 80, and sample standard deviation s is 0.7 hours. Then, the standard error for the mean is,

[tex]\begin{aligned}SE_x&=\frac{s}{\sqrt{n}}\\&=\frac{0.7}{\sqrt{80}}\\&=0.07826\end{aligned}[/tex]

The degree of freedom is given by, df = n-1 = 80-1 = 79.

From the t-distribution table, [tex]t_{\alpha/2, 79}=1.7735[/tex]

Then, the upper-bound 95% confidence interval is calculated as,

[tex]\begin{aligned}\overline{X}+t_{\alpha,(n-1)}\frac{s}{\sqrt{n}}&\geq \mu\\&=\overline{X}+t_{0.08, 79}\frac{s}{\sqrt{n}}\\&=1.5+1.7735\left(\frac{0.7}{\sqrt{80}}\right)\\&=1.5+1.7735(0.07826)\\&=1.5+0.13879\\&=1.63879\\&\approx1.64\end{aligned}[/tex]

The required answer is 1.64.

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a) The probability that an apple from the tree has a weight greater than 90 grams is of: 0.2514 = 25.14%.

b) i) The p-value of the test is of: 0.0045.

b) ii) The conclusion of the test is given as follows: There is enough evidence to conclude that the mean weight of apples from tree A is greater than the mean weight of apples from tree B, as the p-value of the test is less than the significance level.

The z-score of a measure X of a variable that has mean symbolized by [tex]\mu[/tex] and standard deviation symbolized by [tex]\sigma[/tex] is obtained by the rule presented as follows:

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

The mean and the standard deviation of the weight of the apples are given as follows:

[tex]\mu = 85, \sigma = 7.5[/tex]

The probability that an apple from the tree has a weight greater than 90 grams is one subtracted by the p-value of Z when X = 90, hence:

Z = (90 - 85)/7.5

Z = 0.67

Z = 0.67 has a p-value of 0.7486.

1 - 0.7486 = 0.2514 = 25.14%.

For each sample, the mean and the standard error are given as follows:

Hence, for the distribution of differences, the mean and the standard error are given as follows:

The test statistic is given by the division of the mean by the standard error of the distribution of differences, hence:

z = 4.2/1.61 = 2.61.

Using the z-table, with z = 2.61, the p-value is of:

0.0045.

As the p-value is less than the significance level, there is enough evidence to conclude that the mean weight of apples from tree A is greater than the mean weight of apples from tree B.

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She'll need 4 gallons of 15% ethanol gasoline and 5 gallons of 78% ethanol gasoline.

An expression or mathematical expression is a finite collection of symbols that is well-formed according to context-dependent norms.

Here,

The number of gallons required of both kind would be as follows:

4 gallons having 15% ethanol

5 gallons having 78% ethanol

Given that,

The 2 kinds of gases are:

One with 15% ethanol

Other with 78% ethanol

Given that,

The gases(ethanol and gasoline) are diluted in a such a manner that it involves a total of only 50% ethanol.

Number of gallons she wants to use = 9

This shows that only 50% of 9 gallons i.e. 4.5 gallons of ethanol can be used.

Assuming x being the gasoline's measure that is diluted with 15% ethanol.

Now,

The gasoline's measure that is diluted with 78% ethanol would be = 9 - x gallons

Therefore,

x × 15% + (9-x) × 78% = 4.5

On solving, we get

x = 4 gallons

Thus,

The measure of gallons having 15% ethanol = 4

The measure of gallons having 78% ethanol = (9 - x)

= (9 - 4)

= 5 gallons

She will use 4 gallon of 15% ethanol gas and 5 gallon of 78% ethanol gas.

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At a continuous speed of 20 miles per hour, it takes 2 minutes to cross this bridge.

The unitary method is used to calculate the value of a single unit and then multiply that value by itself in order obtain the desired value. Unitary refers to a single, unique, or solitary unit. As a result,

this method's objective is to establish values in terms of a single unit. If a car can drive 44 kilometer two litres of gas, for instance, the unitary approach can be used to calculate how many kilometers it can travel on one litre of gas. The value of a single unit is determined by the unitary technique, and also the value of the required quantity of units can then be calculated using this value.

given,

 0.76 miles = (4024/5280) miles

Speed =20 miles per hour

Time: =(Distance / Speed) = (0.76/20)

= 0.038 ( in hours )

into minutes = 2 min

At a continuous speed of 20 miles per hour, it takes 2 minutes to cross this bridge

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To find the constant of variation in this situation, we need to use the formula for inverse variation, which is:

y = k / x

where y is the number of cigarettes a person smokes, x is the length of time they can hold their breath, and k is the constant of variation.

In this case, we are given that y = 10 cigarettes and x = 50 seconds. We can solve for k by multiplying both sides of the equation by x:

k = y * x

= 10 cigarettes * 50 seconds

= 500

Therefore, the constant of variation in this situation is 500. This means that for every 50 seconds of breath-holding time, a person will smoke approximately 10 cigarettes.

I believe the answer is x= 12

The solutions for the given equation is (1, 12), (2, 18), (3, 24), (4, 30) and (5, 36).

In mathematics, an equation is a formula that expresses the equality of two expressions, by connecting them with the equals sign =.

The given equation is y=6x+6.

The solution of an equation is the set of all values that, when substituted for unknowns, make an equation true.

Substitute, x=1, 2, 3, 4, 5,.....

When x=1

y=6x+6

y=12

When x=2

y=6x+6

y=6(2)+6

y=18

When x=3

y=6x+6

y=6(3)+6

y=24

When x=4

y=6x+6

y=6(4)+6

y=30

When x=5

y=6x+6

y=6(5)+6

y=36

Therefore, the solutions for the equation is (1, 12), (2, 18), (3, 24), (4, 30) and (5, 36).

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The only kind of data generated by observational research is correlations or patterns in the data that have been observed. By using correlations, one variable's value can be used to predict the value of another.

Explanation:

Accurate predictions using data correlation can be ensured by using a variety of methods. Firstly, it is important to ensure that the data is free from errors and is of high quality. This can be done by cleaning and validating the data to remove any inconsistencies and outliers. Secondly, it is important to analyze the data thoroughly and identify any patterns or trends. Furthermore, it is beneficial to use appropriate statistical tests and algorithms such as linear regression, logistic regression, and decision trees to identify the predictive relationships between the variables. Finally, it is important to evaluate the model’s performance to determine the accuracy of the predictions.

The most effective methods for ensuring accurate predictions using data correlation are:

1. Perform Exploratory Data Analysis: Exploratory data analysis is an essential step in any predictive modeling process. It involves exploring the data to identify patterns, trends, and relationships within the data. This helps to identify any potential issues or biases within the data that could affect the accuracy of predictions.

2. Use Statistical Tests: Statistical tests can be used to measure the strength of the relationship between two variables. These tests can help to identify which variables are most strongly correlated with each other and can help to determine which variables should be used in a predictive model.

3. Use Machine Learning Algorithms: Machine learning algorithms can be used to create predictive models that can identify and learn patterns in the data. These algorithms are particularly effective at identifying complex relationships between variables that may not be identified by statistical tests.

4. Validate Predictions: Predictions should always be validated to ensure that they are accurate and reliable. This can be done by comparing the predictions against known outcomes or by testing the model on a separate data set.

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Answer:

36,015.

Step-by-step explanation:

To calculate the cost-of-living increase, you would first multiply the current salary by the percentage increase: $35,000 * 0.029 = $1,015.

Then, to find the new salary, you would add the cost-of-living increase to the current salary: $35,000 + $1,015 = $36,015.

So, the woman's new salary would be $36,015 per year.

Answer:

15 cm

Step-by-step explanation:

a² + b² = c²

(9 cm)² + (12 cm)² = c²

81 cm² + 144 cm² = c²

225 cm² = c²

c = √(225 cm²)

c = 15 cm

Answer: 15 cm

19% of people have a dog,24% of people have a cat , and 14% percentage of people have both 62% of people have either a dog or a cat.

To find the percentage of people that have either a dog or a cat, we need to add the percentage of people that have a dog to the percentage of people that have a cat.

19% + 24% = 43%

Therefore, 62% of people have either a dog or a cat.

43% of people have either a dog or a cat, but do not have both. We can find this by subtracting the percentage of people that have both a dog and a cat from the total percentage.

43% - 14% = 29%

Therefore, 29% of people have a dog or a cat, but not both.

The complete question is:

Suppoe that 19% of people have a dog,24% of people have a cat , and 14% of people have both dog and cat.

What percentage of people have either a dog nor a cat?

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The percentile rank of the score 71 on the test is 26.7.

The value that a specific percentage falls under is known as the percentile. Ben, for instance, is the fourth-tallest child in a group of 20, and eighty percent of the kids are shorter than you.

Given:

58, 64, 66, 70, 71, 75, 77, 80, 84, 85, 87, 90, 93, 95, 96

Calculate the percentile of score 71 as shown below,

[tex]Percentile = n / N \times 100[/tex]

Here, n is the number of scores below 71 and N is the total number of scores,

Percentile = 4 / 15 × 100

Percentile = 0.267 × 100

Percentile = 26.7 percentile

Therefore, the percentile rank of the score 71 on the test is 26.7

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We may demonstrate via a contrapositive assertion that if the total of two real numbers is less than 50, then at least one of the numbers must be less than 25.

The purpose is to demonstrate the following using contraposition:

Take the negation of the hypothesis and the conclusion to produce the conditional statement's opposite. Create the inverted statement first, then swap the hypothesis and conclusion to create the contrapositive of the conditional statement.

Contrapositive assertions, in other words, result from adding "not" to both component claims and reversing the order of the given conditional statements.

Two real numbers will have a sum that is larger than or equal to 50 if neither of them is smaller than 25.

Assume for all real numbers r and s r≥25, s≥25

By using inequality algebra,

r+s≥25+25

≥50

This demonstrates that two numbers will add up to a value more than or equal to 50 if neither of them is less than 25.

Hence, r + s<50, then r<25, s<25 by contrapositive statement.

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