pls help it’s 9th grade math

To determine the necessary sample size to obtain an interval width of 50 ppm for a confidence level of 95%, we need to use the formula for sample size calculation for estimating a population mean.

The formula for sample size calculation is:

n = (Z * σ / E)^2

In this case, the desired margin of error is 50 ppm, which means the interval width is 2 * E = 50 ppm. Therefore, E = 25 ppm.

The Z-score corresponding to a 95% confidence level is approximately 1.96.

Given that the investigators made a rough guess of 175 for the value of σ (standard deviation) before collecting data.

We can substitute these values into the sample size formula:

n = (1.96 * 175 / 25)^2

Simplifying the calculation:

n = (7 * 175)^2

n = 1225^2

n ≈ 1,500,625

Therefore, a sample size of approximately 1,500,625 would be necessary to obtain an interval width of 50 ppm for a confidence level of 95%.

To obtain an interval width of 50 ppm with a confidence level of 95%, a sample size of approximately 1,500,625 is required. This is calculated using the formula for sample size estimation, considering a desired margin of error of 25 ppm and a standard deviation estimate of 175. The Z-score corresponding to a 95% confidence level is used to determine the sample size.

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Jordan's average rate over the last 2 hours of her trip is 9 miles/hour.

To find Jordan's average rate over the last 2 hours of her trip,

we need to calculate the distance she traveled during that time period.

We know that Jordan was initially 20 miles away from her house and after 4 hours, she was 38 miles away. Therefore, she traveled a distance of 38 miles - 20 miles = 18 miles in the first 4 hours.

To find her average rate over the last 2 hours, we divide the distance traveled in those 2 hours by the time taken. The distance traveled in the last 2 hours is 18 miles (since she traveled 18 miles in the first 4 hours), and the time taken is 2 hours.

Average rate = Distance / Time

Average rate = 18 miles / 2 hours

Average rate = 9 miles per hour

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Answer:

if 1 equal to x

and 2 equal to x-4

that mean

(x)+(x-4)=180

2x-4=180

2x=184

x=92

lets start to find the angles that marked with numbers

1=92

2=88

3=88

4=92

5=92

6=88

7=88

8=92

that's it

Have a great day

Answer:

p =43/2

Step-by-step explanation:

8/9 = 12/(p-8)

We can use cross products

8 * (p-8) = 9*12

Distribute

8p - 64 = 108

Add 64 to each side

8p -64+64 = 108+64

8p =172

Divide by 8

8p/8 =172 /8

p =43/2

Answer: p=43/2

Step-by-step explanation:

To solve for p, you would cross multiply.

\(8(p-8)=108\)                 [distribute the 8]

\(8p-64=108\)                  [add 64 on both sides]

\(8p=172\)                          [divide both sides by 8]

\(p=\frac{172}{8}\)                        [simplify the fraction]

\(p=\frac{43}{2}\)

Answer:

7/36

Step-by-step explanation:

7/9* 1/4

Multiply the numerator

7*1 = 7

9*4 = 36

Put the numerator over the denominator

7/36

Answer:

Step-by-step explanation:

7/9 x 1/4 = 7/36

Answer:

The mod-point is (-4,-4)

Step-by-step explanation:

By using mid-point formula

M(x,y)=(x1+x2)/2 ,(y1+y2)/2

putting the values of the coordinates

M(x,y)=(0+-8)/2 ,(-8+0)/2

M(x,y)=-8/2 , -8/2

M(x,y)=(-4,-4)

So the mid-point is (-4.-4)

I hope this will help you :)

Answer: Hi!

To solve this equation, we first distribute to the terms inside of the parentheses.

10*4 = 40

10*-3i = -30i

Our equation now looks like this:

40 - 30i

There is nothing left to simplify, so you're done!

Hope this helps!

the third side must be greater than 8 and less than 16.

To determine the range of possible lengths for the third side of the triangle, we can use the triangle inequality theorem, which states that the sum of any two sides of a triangle must be greater than the third side.

So, for a triangle with sides of 4 and 12, the third side must satisfy:

12 - 4 < third side < 12 + 4

which simplifies to:

8 < third side < 16

what is triangle?

A triangle is a geometric shape with three sides and three angles. It is formed by connecting three non-collinear points in a plane. The sum of the interior angles of a triangle is always 180 degrees, and there are various types of triangles based on their side lengths and angle measures.

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Answer:

$567.5

Step-by-step explanation:

7.5 × 9 is 67.5 and Plus $500 would be $567.5

Answer: 1182

Step-by-step explanation:

Answer: all the ones that do not have a negative sign in front easy.

Answer:

526 X 9= 4734 is the answer.

Answer:

PART 1

In january she recives the discount but not in Febuary

25*12= 300 For Jan

59.99*10= 599.90 For Feb

Total: 899.90 dollars

PART 2

x stands for amount of months

59.99x=359.94

Divide both sides by 59.99

x= 6

Step-by-step explanation:

Probability refers to the measure of the likelihood or chance of an event occurring, expressed as a value between 0 and 1, where 0 represents impossibility and 1 represents certainty.

To find the probability that the driver will find the second traffic light green, we need to make an assumption that the probability of each traffic light being green is independent of the other traffic lights. This means that the probability of finding the second traffic light green is the same as the probability of finding the first traffic light green.

Since the probability of finding the first green light is given as 0.56, the probability of finding the second green light is also 0.56.

Therefore, the probability that the driver will find the second traffic light green is 0.56.

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Answer: 8000

Step-by-step explanation:

From the question, we are informed that the expression 10³ × 2^w models the population of the bacteria after w weeks.

The number of bacteria that will be present in 3 weeks will then be:

= 10³ × 2^w

= 10³ × 2³

= 1000 × 8

= 8000 bacterias

Answer:

the answer is A

Step-by-step explanation:

About 50% of the respondents were at or between 40 and 67.5 years old.

Answer:

Interest = $3,888

Step-by-step explanation:

Formula:

I = prt or I = p · r · t

what it stands for:

I = amount of interest

P = principal amount ($1,200)

R = interest rate (in years)(3% into decimal which would be .03)

T = amount of time (in years)($108)

so:

I = prt

I = (1,200)(.03)(108)

I = $3,888

Interest = $3,888

Answer:

$3.30

Step-by-step explanation:

66 times 0.05

Answer:

4a) 9n - 3

4b) n = 11

Step-by-step explanation:

3(3n - 1)

9n - 3

9n - 3 = 96

9n - 3 + 3 = 96 + 3

9n = 99

9n ÷ 9 = 99 ÷ 9

n = 11

(Hey, angles rock!)

Answer:

45 + 60 = 105

Step-by-step explanation:

ABC consists of two angles, angle ABD and angle DBC. Therefore, the sum of the measures of angles ABD and DBC is the measure of ABC.

45 + 60 = 105

Answer:

2.26 feet

Step-by-step explanation:

400/25=16

16/3.14=5.0955

5.0955^2=2.257

My explanation is that a quadratic equation is a set of terms of the form (in general): ax2+bx+c=0. A quadratic function is one where the right-hand constant (call it f) is allowed to vary with x, thus giving: f(x)=ax2+bc+c.

To compare the posttreatment t-test scores of two groups of subjects who received different treatments, the appropriate analytic statistic would be a two-sample t-test. An independent samples t-test would be appropriate for analyzing the data.

This test is used to determine whether there is a statistically significant difference between the means of two independent groups. The two-sample t-test assumes that the samples are independent, normally distributed, and have equal variances.

If the probability is lower than a predetermined significance level (usually 0.05), then we reject the null hypothesis that the two group means are equal and conclude that there is a statistically significant difference between the treatments.

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The given statement "if you try to match a slope and an intercept at the same time, their mistakes will be related" is TRUE.

A y-intercept, also known as a vertical intercept, is the location where the graph of a function or relation intersects the coordinate system's y-axis.

This is done in analytic geometry using the common convention that the horizontal axis represents the variable x and the vertical axis the variable y.

These points satisfy x = 0 because of this.

The errors of a slope and an intercept will be connected if you fit them simultaneously.

By changing Y to 0 in the equation and figuring out X, you can always determine the X-intercept.

Similarly, by putting X to 0 in the equation and solving for Y, you can always determine the Y-intercept.

Therefore, the given statement "if you try to match a slope and an intercept at the same time, their mistakes will be related" is TRUE.

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Answer:

$2.50

Step-by-step explanation:

Because you got 6 avocados for 15 dollars so you divide 15/6 to find out each unit cost for the avocados

To solve the given differential equations using the method of undetermined coefficients, we need to find a particular solution that satisfies the non-homogeneous equation. So, the general solution is given by: (a) y = y_h + y_p = Ce^(4x) + (-x - 4xe^(-2x) + 8x^2 - 1)e^(-2x) + 8x - 1, (b) y = y_h + y_p = Ce^x + (-x + 22.21e^x)

Let's solve each equation separately:

(a) y' - 4y = 16xe^(-2x) + 8x + 4

Step 1: Solve the associated homogeneous equation:

The homogeneous equation is y' - 4y = 0, which has the solution y_h = Ce^(4x), where C is a constant.

Step 2: Track down a specific non-homogeneous equation solution:

Since the non-homogeneous term contains terms like xe^(-2x) and x, we assume a particular solution of the form:

y_p = (A + Bx)e^(-2x) + Cx + D

Differentiating y_p, we have:

y'_p = (-2A + B - 2Bx)e^(-2x) + C

Substituting y_p and y'_p into the original equation, we get:

(-2A + B - 2Bx)e^(-2x) + C - 4((A + Bx)e^(-2x) + Cx + D) = 16xe^(-2x) + 8x + 4

Matching coefficients of like terms on both sides, we get:

-2A + B - 4A - 4D = 0 (coefficients of e^(-2x))

-2B - 4C = 16x (coefficients of xe^(-2x))

-2A + C = 8x (coefficients of x)

-4D = 4 (constant term)\

Solving these equations, we find A = -1, B = -4, C = 8, and D = -1.

Therefore, the particular solution is:

y_p = (-x - 4xe^(-2x) + 8x^2 - 1)e^(-2x) + 8x - 1

The general solution is given by:

y = y_h + y_p = Ce^(4x) + (-x - 4xe^(-2x) + 8x^2 - 1)e^(-2x) + 8x - 1

(b) y' - y = (2x + xe^2) + 22,21

Step 1: Solve the associated homogeneous equation:

The homogeneous equation is y' - y = 0, which has the solution y_h = Ce^x, where C is a constant.

Step 2: Track down a specific non-homogeneous equation solution:

Since the non-homogeneous term contains terms like 2x, xe^2, and 22.21, we assume a particular solution of the form:

y_p = Ax + B + Cx^2 + De^x

Differentiating y_p, we have:

y'_p = A + C + 2Cx + De^x

Substituting y_p and y'_p into the original equation, we get:

(A + C + 2Cx + De^x) - (Ax + B + Cx^2 + De^x) = (2x + xe^2) + 22.21

Matching coefficients of like terms on both sides, we get:

A - Ax = 2x + xe^2 (coefficients of x)

C - Cx^2 = 0 (coefficients of x^2)

C + D = 22.21 (constant term)

According to the first equation, A = -1.

From the second equation, we have C = 0.

Substituting A = -1 and C = 0 into the third equation, we get D = 22.21.

Therefore, the particular solution is:

y_p = -x + 22.21e^x

The general solution is given by:

y = y_h + y_p = Ce^x + (-x + 22.21e^x)

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Answer:

The value of tan(3π/4) is indeed -1.

Now, to evaluate tan(3π/4 - π), we can use the following trigonometric identity:

tan(a - b) = (tan(a) - tan(b)) / (1 + tan(a)*tan(b))

Applying this identity to the expression tan(3π/4 - π), we get:

tan(3π/4 - π) = (tan(3π/4) - tan(π)) / (1 + tan(3π/4)*tan(π))

Substituting the values of tan(3π/4) = -1 and tan(π) = 0, we get:

tan(3π/4 - π) = (-1 - 0) / (1 + (-1)*0) = -1

So the value of tan(3π/4 - π) is also -1, which is the same as the value of tan(3π/4).

In other words, the value of tan(3π/4 - π) is equal to the value of tan(3π/4) because π is equal to 180 degrees, which is a full rotation. Subtracting a full rotation from an angle simply results in an equivalent angle in the opposite direction. Thus, the values of tangent for both angles remain the same.