The amount of pollutants that are found in waterways near large cities is normally distributed with mean 8.6 ppm and standard deviation 1.3 ppm. 38 randomly selected large cities are studied. Round all answers to 4 decimal places where possible
a. What is the distribution of X?
b. What is the distribution of a?
c. What is the probability that one randomly selected city's waterway will have more than 8.5 ppm pollutants?
d. For the 38 cities, find the probability that the average amount of pollutants is more than 8.5 ppm.
e. For part d), is the assumption that the distribution is normal necessary?
f. Find the IQR for the average of 38 cities.
Q1=__________ ppm
Q3 =_________ ppm
IQR=_________ ppm

Answer:

A) 360

B) 360

Step-by-step explanation:

Part A)

Given that there are a total of 6 people and 4 person subcommittee is to be selected.

Number of ways to select 1st person = 6

Now, 1 person is selected, total persons left are 5

Number of ways to select 2nd person = 5

Now, 1 person is selected, total persons left are 4

Number of ways to select 3rd person = 4

Now, 1 person is selected, total persons left are 3

Number of ways to select 4th person = 3

So, total number of ways = 6[tex]\times[/tex]5[tex]\times[/tex]4[tex]\times[/tex]3 = 360

Part B)

Given that there are a total of 6 people in the committee

Number of ways to select president  = 6

Now, 1 person is selected, total persons left are 5

Number of ways to select vice president = 5

Now, 1 person is selected, total persons left are 4

Number of ways to select secretary = 4

Now, 1 person is selected, total persons left are 3

Number of ways to select treasurer = 3

So, total number of ways = 6[tex]\times[/tex]5[tex]\times[/tex]4[tex]\times[/tex]3 = 360

Answer:

The answer is C (j' 1,4). It is not B J'(4, 1) because the new coordinate is moving 90 degrees clockwise not 180 degrees.

Step-by-step explanation:

J' will have coordinates (1, 4) after  90° clockwise rotation

Graph is a mathematical representation of a network and it describes the relationship between lines and points.

Rectangle JKLM is rotated 90° clockwise about the origin.

On a coordinate plane, rectangle J K L M has points (-4, 1), (-1, 1), (- 1, - 1), (- 4, - 1).

After rotating the rectangle 90° clockwise about the origin, the point J(-4, 1) will be transformed to a new point J' with coordinates (y, -x).

Thus, J' will have coordinates (1, 4).

Therefore,  J' will have coordinates (1, 4) after  90° clockwise rotation

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Answer:B.

Step-by-step explanation: it is better to have empty seats than toforce people to give up their seats.

Answer:

1st Graph

Step-by-step explanation:

Step 1: Find the inverse

y = 2x - 2

x = 2y - 2

x + 2 = 2y

y = (x + 2)/2

Step 2: Graph the inverse

Simply use a graphing calculator and we should see our answer is the top left graph.

Answer:

c

Step-by-step explanation:

plato

lllluvyvyvyvtctctvtvtctvtctctctctctctctvtvyvyvyvyvyvyvtvtv

Answer:

C

Step-by-step explanation:

Recall the equation for a circle:

[tex](x-h)^2+(y-k)^2=r^2[/tex], where the center is (h,k) and the radius is r.

The given equation is:

[tex](x+5)^2+(y+7)^2=21^2[/tex]

Another way to write this is:

[tex](x-(-5))^2+(y-(-7))^2=21^2[/tex]

Thus, we can see that h=-5 and k=-7.

The center is at (-5, -7).

Answer:

A)

Step-by-step explanation:

Answer:

[tex] \dfrac{5x^2 + 5x + 3}{3x^2 + 3x} [/tex]

Step-by-step explanation:

[tex] \dfrac{2x + 3}{3x} + \dfrac{x}{x + 1} = [/tex]

[tex] = \dfrac{(x + 1)(2x + 3)}{(x + 1)(3x)} + \dfrac{(3x)(x)}{(3x)(x + 1)} [/tex]

[tex] = \dfrac{2x^2 + 3x + 2x + 3}{3x^2 + 3x} + \dfrac{3x^2}{3x^2 + 3x} [/tex]

[tex] = \dfrac{2x^2 + 5x + 3 + 3x^2}{3x^2 + 3x} [/tex]

[tex] = \dfrac{5x^2 + 5x + 3}{3x^2 + 3x} [/tex]

Answer:

9

i got it right on my test

The equivalent expressions to 243 Superscript two-fifths will be 9.

Those expressions who might look different but their simplified forms are same expressions are called equivalent expressions.

To derive equivalent expressions of some expression, we can either make it look more complex or simple, we simplify it.

Simplification usually involves making the expression simple and easy to use later,

The given expression is;

[tex]243^{2/5}[/tex]

We know that 2/3 = 0.4

So, the equivalent expressions to the given function;

[tex]243^{0.4}\\\\= 9[/tex]

Thus, The equivalent expressions to 243 Superscript two-fifths will be 9.

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Answer:

([tex]\sqrt{15}[/tex])/7

Step-by-step explanation:

Let b be the tird side of the triangle

tanθ= b/c

using the pythagorian theorem we get :

a²+b²= c² ⇒ b²= c²-a²= 8²-7²=15 ⇒b=√15

so: tanθ= √15/7

Answer:

Well I took it"s Reflect the intermediate image.  and Multiply the vertices of polygon ABCD by One-half.

Step-by-step explanation:

Answer:

2 and 5 or B and E

Step-by-step explanation:

i did it on edge! ; )

Answer:

For this case we know that the price after the 12% of discount is 156 and we want to findd the net price so then we can use the following proportional rule:

[tex] \frac{x}{100} = \frac{156}{100-12}[/tex]

Where x represent the net price. And if we solve for the value of x we got:

[tex] x= 100 *\frac{156}{88}= 177.273[/tex]

So then the net price for this case would be $ 177.273

Step-by-step explanation:

For this case we know that the price after the 12% of discount is 156 and we want to findd the net price so then we can use the following proportional rule:

[tex] \frac{x}{100} = \frac{156}{100-12}[/tex]

Where x represent the net price. And if we solve for the value of x we got:

[tex] x= 100 *\frac{156}{88}= 177.273[/tex]

So then the net price for this case would be $ 177.273

Answer:

  270

Step-by-step explanation:

  f(5) = 7 +4·5 = 27

  g(5) = 1/(2·5) = 1/10

The ratio of functions is the ratio of their individual values:

  (f/g)(5) = f(5)/g(5) = 27/(1/10)

  (f/g)(5) = 270

Explanation:

Surface area of a cone = pi*r^2 + pi*r*sqrt(r^2+h^2)

r = radius

h = height of cone

In this case,

r = 8 is the radius

h = 41

So,

SA = surface area

SA = pi*r^2 + pi*r*sqrt(r^2+h^2)

SA = pi*8^2 + pi*8*sqrt(8^2+41^2)

SA = 1250.936884057 use a calculator for this step

SA = 1251 square meters approximately

Answer:

  (–ꝏ, 0) U (0, 5)

Step-by-step explanation:

The relation can be written as ...

  x³ < 5x²

  x³ -5x² < 0

  x²(x -5) < 0

This is not true for x = 0. It is true for x < 5, otherwise. Then the solution set is ...

  x ∈ {(–ꝏ, 0) U (0, 5)}

Answer:

C

Step-by-step explanation:

got it right on edge

Answer:

24 feet.

Step-by-step explanation:

The side  of the square = √36 = 6 feet.

The square has 4 equal sides so the perimeter = 4*6 = 24 feet.

Answer:

2x-y=4

Step-by-step explanation:

Standard form of a line: Ax+by=c

Use slope intercept form: y=mx+b

slope= 2

y=2x-4

Add 4 to both sides.

y+4=2x

subtract y from both sides.

4=2x-y

Rotate the equation

2x-y=4

Answer:

2x-y=4

Step-by-step explanation:

y=2x-4 is the slope intercept.

y-2x=-4

-2x+y=-4

2x-y=4

hello

[tex]A-B=\left[\begin{array}{cc}4-(-2)&7-5\\-3-7&8-(-1)\\-5-(-3)&-2-2\end{array}\right] \\\\=\left[\begin{array}{cc}4+2&2\\-10&8+1\\-5+3&-4\end{array}\right] \\\\=\left[\begin{array}{cc}6&2\\-10&9\\-2&-4\end{array}\right][/tex]

hope this helps

Using matrices A  and B, the result of A-B is

[tex]A-B=\left[\begin{array}{ccc}6&2\\-10&9\\-2&-4\end{array}\right][/tex]

Given :

Two matrices A  and B. We need to subtract both matrix

Lets find out A-B

Given matrices  A  and B  are

[tex]A=\left[\begin{array}{ccc}4&7\\-3&8\\-5&-2\end{array}\right] \\B=\left[\begin{array}{ccc}-2&5\\7&-1\\-3&2\end{array}\right][/tex]

When we subtract A-B  we need to subtract the corresponding elements in that matrix

[tex]A-B=\left[\begin{array}{ccc}4&7\\-3&8\\-5&-2\end{array}\right] -\left[\begin{array}{ccc}-2&5\\7&-1\\-3&2\end{array}\right]=\left[\begin{array}{ccc}4-(-2)&7-5\\-3-7&8-(-1)\\-5-(-3)&-2-2\end{array}\right] \\A-B=\left[\begin{array}{ccc}6&2\\-10&9\\-2&-4\end{array}\right][/tex]

The above is the resultant matrix .

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Answer:

  x ║ z

Step-by-step explanation:

Lines parallel to the same line are parallel to each other.

x and z are both parallel to y, so are parallel to each other:

  x ║ z

Answer:

a). Horizontal distance = 11.1 m

b). Maximum height = 6.2 m

c). Firefighter is 13.7 m from the house

Step-by-step explanation:

Given question is incomplete; find the complete question in the attachment.

Height of the water can be determined by the expression,

h(x) = -0.026x²+ 0.577x + 3

Here x = Horizontal distance of the from the firefighter

a). Since the stream of the water will follow a parabolic path, maximum point of the parabola will be = Vertex of the parabolic path

Horizontal distance from the firefighter at which the water achieves the maximum height = -[tex]\frac{b}{2a}[/tex]

From the quadratic function,

h(x) = -0.026x²+ 0.577x + 3

a = -0.026

b = 0.577

Therefore, the horizontal distance = [tex]-\frac{0.577}{2\times (-0.02612)}[/tex] = 11.05 m

                                                         ≈ 11.1 meters

b). By putting x = 11.1 in the quadratic equation,

    h(x) = -0.02612(11.1)²+ 0.577(11.1) + 3

           = -3.2182 + 6.4047 + 3

           = 6.18 m

           ≈ 6.2 m

c). For h(x) = 6 m

    6 = -0.02612x² + 0.577(x) + 3

    0.02612x² - 0.577x + 3 = 0

    From quadratic formula,

    x = [tex]\frac{-b\pm\sqrt{b^2-4ac}}{2a}[/tex]

    x = [tex]\frac{0.577\pm \sqrt{(-0.577)^2-4(0.02612)(3))}}{2(0.02612)}[/tex]

    x = [tex]\frac{0.577\pm\sqrt{0.019489}}{0.05224}[/tex]

    x = [tex]\frac{0.577\pm0.1396}{0.05224}[/tex]

    x = 13.7 m, 8.37 m

Therefore, the farthest distance of the firefighter from the house will be 13.7 m

Answer:

Its the first answer choice.

Step-by-step explanation:

Its open circle because the sign is just greater than. And since x is an absolute value, the negative sign doesnt matter so, it points to the right of 10 and to the left of -10.

Answer:

the probability that 7 out 10 Internet users will order something online is 0.78 or 78%

Step-by-step explanation:

Given that:

Internet users who order something online = 85%

To find:

Probability that 7 out of 10 Internet users will order something online ?

Solution:

This problem is of binomial distribution of probability.

where, p = 0.85

q = 1-p = 0.15

r = 7 and

n = 10

Formula is given as:

[tex]P(x = r) = _nC_r q^{n-r}p^r[/tex]

Putting all the values:

[tex]P(x = 7) = _{10}C_7 0.15^{10-7}\times 0.85^7\\P(x = 7) = _{10}C_3 0.15^{3}\times 0.85^7\\P(x = 7) = 10\times 9 \times 8 \times 0.15^{3}\times0.85^7\\P(x = 7) = 720 \times .0034 \times0.32\\P(x = 7) = 0.78[/tex]

So, the probability that 7 out 10 Internet users will order something online is 0.78 or 78%.

Answer:

[tex] P(38.6 <X <57.8)[/tex]

And we can assume a normal distribution and then we can solve the problem with the z score formula given by:

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

And replacing we got:

[tex] z=\frac{38.6- 45}{16}= -0.4[/tex]

[tex] z=\frac{57.8- 45}{16}= 0.8[/tex]

We can find the probability of interest using the normal standard table and with the following difference:

[tex] P(-0.4 <z<0.8)= P(z<0.8) -P(z<-0.4) = 0.788-0.345= 0.443[/tex]

Step-by-step explanation:

Let X the random variable who represent the expense and we assume the following parameters:

[tex]\mu = 45, \sigma 16[/tex]

And for this case we want to find the percent of his expense between 38.6 and 57.8 so we want this probability:

[tex] P(38.6 <X <57.8)[/tex]

And we can assume a normal distribution and then we can solve the problem with the z score formula given by:

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

And replacing we got:

[tex] z=\frac{38.6- 45}{16}= -0.4[/tex]

[tex] z=\frac{57.8- 45}{16}= 0.8[/tex]

We can find the probability of interest using the normal standard table and with the following difference:

[tex] P(-0.4 <z<0.8)= P(z<0.8) -P(z<-0.4) = 0.788-0.345= 0.443[/tex]

Answer:

So if you increase the sample size used to construct a given confidence interval, the confidence interval will be narrower, that is, more precise.

Step-by-step explanation:

The sample size is important to find the margin of errror of a confidence interval.

The margin of error is given by a formula in the following format:

[tex]M = \frac{c*s}{\sqrt{n}}[/tex]

In which c is the critical value(depends on the distribution used, can be T or Z), s is the standard deviation(of the sample or the population) and n is the size of the sample.

As n increases, M decreases, which leads to a lower margin of error.

The lower the margin of error, the more precise the interval is.

So if you increase the sample size used to construct a given confidence interval, the confidence interval will be narrower, that is, more precise.

Answer:

  [tex]y=\log_3{(x+3)}[/tex]

Step-by-step explanation:

The parent log function has a vertical asymptote at x=0, so the asymptote at x=-3 indicates a left shift of 3 units.

The parent log function crosses the x-axis 1 unit to the right of the vertical asymptote, which this one does, indicating there is no vertical shift.

The parent log function has an x-value equal to its base when it has a y-value of 1. Here, the y-value of 1 corresponds to an x-value 3 units to the right of the vertical asymptote, so the base of this logarithm is 3.

The function is ...

  [tex]\boxed{y=\log_3{(x+3)}}[/tex]

Answer:

  y = √(900 -x²); see below for a graph

Step-by-step explanation:

The high point (30 ft) is the radius of the circle, so the equation is ...

  x² +y² = 30²

Subtract the x-term and take the square root to find y.

  y² = 30² -x²

  y = √(30² -x²) = √(900 -x²)

The graph is shown in the attachment.

_____

Comment on "how that website works"

We don't know what web site you're referring to, but the one I like is Desmos. It only takes a few minutes to learn to graph the equation here.

You don't even need to solve for y to get the desired graph. You can simply specify that y ≥ 0.

━━━━━━━☆☆━━━━━━━

▹ Answer

r = 4

▹ Step-by-Step Explanation

15r - 6r = 36

Collect like terms

9r = 36

Divide

r = 4

Final Answer

r = 4

Hope this helps!

- CloutAnswers ❁

Brainliest is greatly appreciated!

━━━━━━━☆☆━━━━━━━

Answer: The answer would be 4, which is B, hopefully this helps.

Answer:

Net sales is $ 504285.71

Step-by-step explanation:

We have the following:

Let net sales be x.

Net sales - Cost of goods sold = Gross profit

We replace and we are left with:

x - $ 353000 = x * 30%

x - $ 353000 = 0.30 * x

x - 0.30 * x = $ 353000

0.7 * x = $ 353000

x = $ 353000 / 0.7

x = $ 504285.71

Therefore, net sales is $ 504285.71

Answer:

[tex]f^{-1} = \frac{x-1}{2}[/tex]

Step-by-step explanation:

[tex]f(x) = 2x+1[/tex]

Replace it with y

[tex]y = 2x+1[/tex]

Exchange the values of  x and y

[tex]x = 2y+1[/tex]

Solve for y

[tex]x = 2y+1[/tex]

Subtracting 1 from both sides

[tex]2y = x-1[/tex]

Dividing both sides by 2

[tex]y = \frac{x-1}{2}[/tex]

Replace it by [tex]f^{-1}[/tex]

So,

[tex]f^{-1} = \frac{x-1}{2}[/tex]

Answer:

[tex]\displaystyle f^{-1}(x)= \frac{1}{2}x - \frac{1}{2}[/tex]

Step-by-step explanation:

f(x) = 2x + 1

f(x) = y (output)

y = 2x + 1

Solve for x.

y - 1 = 2x

Divide 2 on both sides.

y/2 - 1/2 = x

1/2y - 1/2 = x

Switch variables.

1/2x - 1/2 = y

[tex]f^{-1}(x)= \frac{1}{2}x - \frac{1}{2}[/tex]

Answer:

The new salary of that person (for the period of a year) would be [tex]\$ 16,\!275[/tex].

Step-by-step explanation:

Start by considering: what is the exact value (in dollars) of that "[tex]5\%[/tex] raise in salary"?

[tex]5\%[/tex] (five percent) is equal to [tex]\displaystyle \frac{5}{100}[/tex].

To find the value of [tex]5\%[/tex] of [tex]\$15,\!500[/tex], simply multiply [tex]\$15,\!500[/tex] by [tex]5\%[/tex]:

[tex]\begin{aligned}&5\% \times \$15,\!500\\ &= \frac{5}{100} \times \$15,\!500 \\ &= 5\times \$155 = \$775 \end{aligned}[/tex].

Add that to the original (one-year) salary of this person to find the new one-year salary:

[tex]\$15,\!500 + \$775 = \$16,\!275[/tex].

Answer:

The new salary is $16,725

Step-by-step explanation:

To find the new salary, multiply 5% and $15,500

5% * $15,500

First, convert 5% to a decimal. Divide 5 by 100 or move the decimal place 2 spaces to the left.

5/100=0.05

5.0 --> 0.5--> 0.05

0.05 * $15,500

Multiply

$775

The raise is equal to $775.

Next, add the raise to the salary.

raise + salary

The raise is $775 and the salary is $15,500

$775 + $15,500

Add

$16,275

The new salary is $16,275