A poll agency reports that 75% of teenagers aged 12-17 own smartphones. A random sample of 234 teenagers is drawn. Round your answers to four decimal places as needed. Part 1. Find the mean . Part 2. out of 6 Find the standard deviation

Answer:

B

Step-by-step explanation:

Answer:

20 years old.

Step-by-step explanation:

Let us say that the man's age is represented by x and the son's age is represented by y.

As of now, x = 2y.

In 20 years, both ages will increase by 20. We can have an equation where the son's age increased by 20 equals 2/3 of the man's age plus 20.

(y + 20) = 2/3(x + 20)

Since x = 2y...

y + 20 = 2/3(2y + 20)

3/2y + 30 = 2y + 20

2y + 20 = 3/2y + 30

1/2y = 10

y = 20

To check our work, the man's age is currently double his son's, so the man is 40 and the son is 20. In 20 years, the man will be 60 and the son will be 40. 40 / 60 = 2/3, so the son's age is 2/3 of his father's.

So, the son's present age is 20 years old.

Hope this helps!

First find the distance it is reflected:

D = 20.0 x 10.0 /(20-10) = 200/10 = 20cm away.

Now calculate the magnification: -20/ 20 = -1

Now calculate the height:

-1 x 2.50 = -2.50

The negative sign means the image is inverted.

The mirrored image would be inverted, 2.50 cm tall and 20 cm in front of the mirror.

Answer:

[tex] 3x - y = 5 [/tex]

Step-by-step explanation:

The two pint equation of a line:

[tex] y - y_1 = \dfrac{y_2 - y_1}{x_2 - x_1}(x - x_1) [/tex]

We have

[tex] x_1 = 4 [/tex]

[tex] x_2 = 3 [/tex]

[tex] y_1 = 7 [/tex]

[tex] y_2 = 4 [/tex]

[tex] y - 7 = \dfrac{4 - 7}{3 - 4}(x - 4) [/tex]

[tex] y - 7 = \dfrac{-3}{-1}(x - 4) [/tex]

[tex] y - 7 = 3(x - 4) [/tex]

[tex] y - 7 = 3x - 12 [/tex]

[tex] 5 = 3x - y [/tex]

[tex] 3x - y = 5 [/tex]

Answer:

D. *6F

Step-by-step explanation:

C=(F-32)*5/9

30=(F-32)*5/9

F = (30*9)/5+32

F = 86

Answer:

C(d) = d(2.25) + m(0.3)

Step-by-step explanation:

A taxi company charges $2.25 per ride plus $0.30 per mile.

Let d represent number of rides..

Let m represent number of Miles...

Then let C represent the total cost for each ride at a specific number of Miles.

The linear model representing the cost as a function of d the total ride

C(d) = d(2.25) + m(0.3)

The values stand independently because the customer can choose a different right and a different mile.

Answer:

I didn't know which one you wanted...

Step-by-step explanation:

1. Finding the x an y-intercepts

To find the x-intercept, substitute in 0 for y and solve for x. To find the y-intercept, substitute in 0 for x and solve for y.

x-intercept(s): (2,0)

y-intercept(s): (0,−24)

2. Finding the slope and y-intercept

Use the slope-intercept form to find the slope and y-intercept.

Slope: 12

y-intercept: −24

Answer:

2.5 meters per second

Step-by-step explanation:

9x1000=9000m/h

9000/60/60=2.5m/s

Answer:

2.5 m/s

Step-by-step explanation:

convert kilometers to meters and then use a conversion calc to do the rest

Answer:

A. [tex]\frac{9}{10}[/tex]

B. 1

C. [tex]\frac{2}{6}[/tex] or [tex]\frac{1}{3}[/tex]

D. [tex]\frac{2}{30}[/tex] or [tex]\frac{1}{15}[/tex]

E. [tex]\frac{12}{70}[/tex] or [tex]\frac{6}{35}[/tex]

F. [tex]\frac{6}{90}[/tex] or [tex]\frac{1}{15}[/tex]

G. [tex]\frac{9}{32}[/tex]

H. [tex]\frac{4}{15}[/tex]

Answer:

Step-by-step explanation:

Reducing the given expressions to the lowest terms:

A. 3/10 + 6/10:

B. 1/3 + 1/4 + 1/6:

C. 5/6-3/6:

D. 2/3-6/10:

E. 4/10*3/7:

F. 1/6*6/15:

G. 1/8 divided by 4/9:

H. 1/5 divided by 3/4:

Answer:

a) Expected Value of Claims = $32,000

b) Average premium per claim, in order to break-even on claim costs

= $5,333.33

c) To make a profit of $60 per policy (i.e. a total profit of $360 ($60 x 6), it must charge:

= $5,393.33 per policy

Step-by-step explanation:

a) Data and Calculations:

Amount of Claim      Probability   Expected Value

$0                               0.60             $0

$50,000                     0.25             $12,500

$100,000                   0.09                 9,000

$150,000                   0.04                 6,000

$200,000                  0.01                 2,000

$250,000                 0.01                 2,500

Expected Cost of claims =          $32,000

b) Average premium per claim, in order to break-even on claim costs

= Total Claim cost divided by number of policies

= $32,000/6 = $5,333.33

c) To make a profit of $60 per policy (i.e. a total profit of $360 ($60 x 6), it must charge:

Total Claim cost + Total profit / 6 or Average Premium plus Profit per policy =

= ($32,000 + $360)/6 or $5,333.33 + $60

= $32,360/6 or $5,393.33

= $5,393.33

The total expected value is $32000, the average premium so that it breaks even on its claim  costs are $5333.33 and the company charge to make a profit of $60 per policy is $5393.33.

Given :

The table shows claims and their probabilities for an insurance company.

Amount of Claim          Probability               Expected Value

$0                                      0.60                             0

$50000                             0.25                            $12500

$100000                            0.09                            $9000

$150000                            0.04                             $6000

$200000                           0.01                              $2000

$250000                            0.01                             $2500

A) So, the total expected value is = 12500 + 9000 + 6000 + 2000 + 2500

                                                   =  $32000

B) The average premium is given by:

[tex]=\dfrac{32000}{6}[/tex]

= $5333.33

C) The company charge to make a profit of $60 per policy is:

[tex]= \dfrac{32000+360}{6}[/tex]

[tex]=\dfrac{32360}{6}[/tex]

= $5393.33

For more information, refer to the link given below:

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Answer:

  (x, y, z) = (13/7, 19/7, 25/7)

Step-by-step explanation:

You know that the vector whose components are the coefficients of the equation of the plane is perpendicular to the plane. That is (1, 2, 3) is a vector perpendicular to the plane.

The parametric equation for a line through (1, 1, 1) with this direction vector is ...

  (x, y, z) = (1, 2, 3)t +(1, 1, 1) = (t+1, 2t+1, 3t+1)

The point of intersection of this line and the plane will be the point in the plane closest to (1, 1, 1). That point has a t-value of ...

  (t +1) +2(2t +1) +3(3t +1) = 18

  14t +6 = 18

  t = 12/14 = 6/7

The point in the plane closest to (1, 1, 1) is ...

  (x, y, z) = (6/7+1, 2(6/7)+1, 3(6/7)+1)

  (x, y, z) = (13/7, 19/7, 25/7)

Hey there! :)

Answer:

y = 1/4x - 3.

Step-by-step explanation:

Use the slope-formula to find the slope of the line:

[tex]m = \frac{\text{rise}}{\text{run}} = \frac{y_2 - y_1}{x_2 - x_1}[/tex]

Plug in two points from the line. Use the points (-4, -4) and (0, 3):

[tex]m = \frac{-3 - (-4)}{0 - (-4)}[/tex]

Simplify:

m = 1/4.

Slope-intercept form is y = mx + b.

Find the 'b' value by finding the y-value at which the graph intersects the y-axis. This is at y = -3. Therefore, the equation is:

y = 1/4x - 3.

Answer:

Step-by-step explanation:

Given that:

mean (μ) = 476 grams, standard deviation (σ) = 36 grams. P(z) = 19%

The z score shows by how many standard deviation the raw score is above or below the mean. It is given by the equation:

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

Since the 19% weigh more, therefore 81% (100% - 19%) weigh less.

From the normal distribution table, the z score that corresponds to a probability of 81%(0.81) = 0.87

We substitute z = 0.88 in the z score equation to find the raw score. Therefore:

[tex]z=\frac{x-\mu}{\sigma}\\0.87=\frac{x-476}{36}\\ x-476=31.32\\x=31.32+476\\x=507.32\\[/tex]

x ≅ 507 grams

Therefore 19% of fruits weigh more than 507 grams

Answer:

15 49-cent stamps

Step-by-step explanation:

We can solve this problem with the equations 0.49(x) + 0.21(y) = 9.45 and x - 5 = y. Well, 0.49(15) + 0.21(10) = 9.45, so we know that there are 15 49-cent stamps and 10 21-cent stamps. The question is asking for the number of 49-cent stamps, so we can tell Travis bought 15 49-cent stamps.

Hope this helps! Plz give me brainliest, it will help me achieve my next rank.

The number of 49-cent stamps that Travis bought given the equation is 15.

Given this equation: 0.49s+0.21(s−5)=9.45 take the following steps to determine the value of s

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Answer:

The chance that there will be exactly 2 heads among the first five tosses and exactly 4 heads among the last 5 tosses is P=0.0488.

Step-by-step explanation:

To solve this problem we divide the tossing in two: the first 5 tosses and the last 5 tosses.

Both heads and tails have an individual probability p=0.5.

Then, both group of five tosses have the same binomial distribution: n=5, p=0.5.

The probability that k heads are in the sample is:

[tex]P(x=k)=\dbinom{n}{k}p^k(1-p)^{n-k}=\dbinom{5}{k}\cdot0.5^k\cdot0.5^{5-k}[/tex]

Then, the probability that exactly 2 heads are among the first five tosses can be calculated as:

[tex]P(x=2)=\dbinom{5}{2}\cdot0.5^{2}\cdot0.5^{3}=10\cdot0.25\cdot0.125=0.3125\\\\\\[/tex]

For the last five tosses, the probability that are exactly 4 heads is:

[tex]P(x=4)=\dbinom{5}{4}\cdot0.5^{4}\cdot0.5^{1}=5\cdot0.0625\cdot0.5=0.1563\\\\\\[/tex]

Then, the probability that there will be exactly 2 heads among the first five tosses and exactly 4 heads among the last 5 tosses can be calculated multypling the probabilities of these two independent events:

[tex]P(H_1=2;H_2=4)=P(H_1=2)\cdot P(H_2=4)=0.3125\cdot0.1563=0.0488[/tex]

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▹ Answer

-17 isn't a natural number

▹ Step-by-Step Explanation

Positive integers are only natural numbers, meaning negative numbers aren't natural numbers.

Hope this helps!

- CloutAnswers ❁

Brainliest is greatly appreciated!

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Answer:

The total number of ways to select 2 CDs from 8 CDs is 28.

Answer:

0.3 m/s

Step-by-step explanation:

The first thing is to attach the allusive graphic to the question. Now yes, let's move on to the solution that would be:

If the through is completely filtered the its volume will:

V = l * [1/2 w * h] = 1/2 l * w * h

Now we derive with respect to time and we are left with:

dV / dt = 1/2 * l * w * dh / dt

We solve by dh / dt and we have:

dh / dt = (2 / (l * w)) * (dV / dt)

We know that l = 8 and w = 5, in addition to dV / dt = 6, we replace:

dh / dt = (2 / (8 * 5)) * (6)

dh / dt = 0.3

Therefore the rate at which the height of the water changes is 0.3 m / s

Answer:

[tex] P(A) = 0.25, P(B= 0.3[/tex]

And if we want to find [tex] P(A \cap B)[/tex] we can use this formula from the definition of independent events :

[tex] P(A \cap B) =P(A) *P(B) = 0.25*0.3= 0.075[/tex]

And the best option would be:

[tex] P(A \cap B) =0.075[/tex]

Step-by-step explanation:

For this case we have the following events A and B and we also have the probabilities for each one given:

[tex] P(A) = 0.25, P(B= 0.3[/tex]

And if we want to find [tex] P(A \cap B)[/tex] we can use this formula from the definition of independent events :

[tex] P(A \cap B) =P(A) *P(B) = 0.25*0.3= 0.075[/tex]

And the best option would be:

[tex] P(A \cap B) =0.075[/tex]

Answer

so I need to know the coordinates for me to tell you the answer but I think I can still help you by explaining.

In order for E to become E' the rule for reflection over y=x is (y, x) so you basically switch the x and the Y to have E'. so for you to be able find out E, you need to witch the x and the y.

for example:

if E' was (-2, 3)

E in the pre image would be (3, -2)

hope this helps :)

Answer:

(-2,6)

Step-by-step explanation:

Just did it edge 2021

Answer:

78 grams

Step-by-step explanation:

20% is 1/5

1/5 of 65 is 13

65 + 13 = 78

brainliest?

Answer:

A) Null hypothesis; H0: μ1 − μ2 ≤ 0

Alternative hypothesis; Ha: μ1 − μ2 > 0

B) Test statistic = t = 1.878

C) p-value is 0.038823.

D) Reject the Null hypothesis H0

Step-by-step explanation:

We are given;

α = 0.05

n1 = 16

n2 = 10

bar x1 = 6.82

bar x2 = 6.28

s1 = 0.65

s2 = 0.75

A) The hypothesis is as follows;

Null hypothesis; H0: μ1 − μ2 ≤ 0

Alternative hypothesis; Ha: μ1 − μ2 > 0

B) Formula yo determine the test statistic is;

t = ((bar x1) - (bar x))/√((s1)²/n1) + (s2)²/n2))

Plugging in the relevant values, we have;

t = (6.82 - 6.28)/√((0.65)²/16) + (0.75)²/10))

t = 0.54/√(0.02640625 + 0.05625)

t = 0.54/0.2875

t = 1.878

C) The formula for the degree of freedom is;

Δ = [(s1)²/n1) + (s2)²/n2))]²/[((s1²/n1)²/(n1 - 1)) + ((s2²/n2)²/(n1 - 1))  

Plugging in the relevant values, we have;

Δ = [(0.65)²/16) + (0.75)²/10))]²/[((0.65²/16)²/(16 - 1)) + ((0.75²/10)²/(10 - 1))  

Δ = 0.00683205566/(0.000046486 + 0.0003515625)

Δ ≈ 17

Thus, the P-value;

From online p-value calculator from t-score and DF which i attached, we have the p-value as;

The p-value is 0.038823.

D) The p-value result is significant at p < 0.05

Thus, we reject the Null hypothesis H0

A) Null hypothesis: μ1 − μ2 ≤ 0

B) Test statistic = t = 1.878

C) The p-value is 0.038823.

D) Reject the Null hypothesis H0.

What all information we have ?

α = 0.05

n1 = 16

n2 = 10

bar x1 = 6.82

bar x2 = 6.28

s1 = 0.65

s2 = 0.75

Part A)

The hypothesis is as follows;

Null hypothesis; H0: μ1 − μ2 ≤ 0

Alternative hypothesis; Ha: μ1 − μ2 > 0

Part B)

The formula to determine the test statistic is :

t = ((bar x1) - (bar x))/√((s1)²/n1) + (s2)²/n2))

t = (6.82 - 6.28)/√((0.65)²/16) + (0.75)²/10))

t = 0.54/√(0.02640625 + 0.05625)

t = 0.54/0.2875

t = 1.878

The formula to determine the test statistic is t = 1.878.

Part C)

The formula for the degree of freedom is;

Δ = [(s1)²/n1) + (s2)²/n2))]²/[((s1²/n1)²/(n1 - 1)) + ((s2²/n2)²/(n1 - 1))  

Δ = [(0.65)²/16) + (0.75)²/10))]²/[((0.65²/16)²/(16 - 1)) + ((0.75²/10)²/(10 - 1))  

Δ = 0.00683205566/(0.000046486 + 0.0003515625)

Δ ≈ 17

Thus, the P-value is 0.038823.

Part D)

The p-value result is significant at p < 0.05 is :

Thus, we reject the Null hypothesis H0.

Learn more about "Hypothesis":

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Answer:

b. False.

Step-by-step explanation:

According to the presented information, at the 95% confidence level, the mean number of coats owned will be between 3.1 and 5.2. That does not mean that there is a 95% chance that they will own that many coats; just that you are 95% confident that they will own the coats.

Hope this helps!

Answer:

35 students

Step-by-step explanation:

Take the number of students in the class and multiply by 60% and see if you get an integer number

28 * .60 =16.8  not an integer

32 * .6 =19.2

35 * .6 =21  yes

39*.6 =23.4

Answer:

54

give me brainliest please please please and follow my page

Step-by-step explanation:

To find length of KC...we need to find the length of HM and MU first ...

so....HM= 96- 78 = 14

JU = 96 + HM = 96 + 14 = 110

....

KU = 110 - JK = 110 - 82 = 28

....

UN = 105+ 82 -( 96 + 14 )

187 - 110

= 77

UC = 77 - 51 = 26

KC = UC + KU = 26 + 28 = 54

The length of [tex]\overline{KC}[/tex] along line [tex]\overline{JN}[/tex] is given as 54 (Option A) See the computation below.

To determine the length of [tex]\overline{KC}[/tex], the length of [tex]\overline{HM}[/tex] and [tex]\overline{MU}[/tex]must first be derived.

[tex]\overline{HM}[/tex] = 96 - 78

[tex]\overline{HM}[/tex] = 14

[tex]\overline{JU}[/tex] = 96 + [tex]\overline{HM}[/tex]

= 96 + 14

[tex]\overline{JU}[/tex]= 110

[tex]\overline{KU}[/tex] = 110 - [tex]\overline{JK}[/tex]

= 110 - 82

[tex]\overline{KU}[/tex]= 28

[tex]\overline{UN}[/tex] = 105+ 82 -( 96 + 14 )

=187 - 110

[tex]\overline{UN}[/tex]= 77

[tex]\overline{UC}[/tex] = 77 - 51

[tex]\overline{UC}[/tex]= 26

Thus,

[tex]\overline{KC}[/tex] = [tex]\overline{UC}[/tex] + [tex]\overline{KU}[/tex]

[tex]\overline{KC}[/tex]= 26 + 28

[tex]\overline{KC}[/tex]= 54

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Answer:

1 because jahahdhekskdbsks

Answer:

3.26%

Step-by-step explanation:

The computation of the probability that she is a student is shown below:

Percentage of student developers = 25.8% = SD

The Percentage of the developer is student = 7.4% = DS

The percentage of the developer is not student = 76.4% = ND

Based on this, the probability is

[tex]= \frac{SD \times DS}{SD \times DS + DS \times ND}[/tex]

[tex]= \frac{25.8\% \times 7.4\%}{25.8\% \times 7.4\% + 7.4\% \times 76.4\%}[/tex]

=3.26%

we simply considered all the elements

This is a great question!

When we are given ( r - c )( 3 ), we are being asked to take 3 as x in the functions r( x ) and c( x ), taking the difference of each afterwards -

[tex]r( 3 ) = ( 3 )^2 + 5( 3 ) + 14,\\x( 3 ) = ( 3 )^2 - 3( 3 ) + 4[/tex]

____

Let us calculate the value of each function, determine their difference, and multiply by 100, considering r( x ) and c( x ) are measured in hundreds of dollars,

[tex]r( 3 ) = 9 + 15 + 14 = 38,\\x( 3 ) = 9 - 9 + 4 = 0 + 4 = 4\\----------------\\( r - c )( 3 ) = 38 - 4 = 34,\\34 * 100 = 3,400( dollars )\\\\Solution = 3,400( dollars )[/tex]

Therefore, ( r - c )( 3 ) " means " that George's new store will have a profit of $3,400 after it's third month in business, given the following options,

( 1. The new store will have a profit of $3400 after its third month in business.  

( ​​2. The new store will have a profit of $2400 after its third month in business.

( 3. ​The new store will sell 2400 items in its third month in business.

( 4. The new store will sell 3400 items in its third month in business.

The required answer is , [tex](r-c)(5)[/tex] means the revenue less expenses in 5 months i.e. the new store will have a profit of $ 5400 after 5 months.

The substitution method is the algebraic method to solve simultaneous linear equations.

Given function is,

[tex]r(x) = x^2+5x+14[/tex]...(1)

And [tex]c(x) = x^2-4x+5[/tex]...(2)

Now, substituting the value into the equation (1) and (2).

[tex]r(5) = (5)^2+5(5)+14=64[/tex]

[tex]c(5) = (5)^2-4(5)+5=10[/tex]

Therefore,

[tex](r-c)(5)=r(5)-c(5)\\=64-10\\=54[/tex]

Now, [tex](r-c)(5)[/tex] means the revenue less expenses in 5 months i.e. the new store will have a profit of $ 5400 after 5 months.

Learn more about the topic Substitution:

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Answer:

[tex]b = 5 \sqrt{3} \ or\ b = -5 \sqrt{3}[/tex]

Step-by-step explanation:

Given

[tex]f(b) = b^2 - 75[/tex]

Required

Determine the roots

To get the root of the function, then f(b) must be 0;

i.e. f(b) = 0

So, the expression becomes

[tex]0 = b^2 - 75[/tex]

Add 75 to both sides

[tex]75 + 0 = b^2 - 75 + 75[/tex]

[tex]75 = b^2[/tex]

Take square roots of both sides

[tex]\sqrt{75} = \sqrt{b^2}[/tex]

[tex]\sqrt{75} = b[/tex]

Reorder

[tex]b = \sqrt{75}[/tex]

Expand 75 as a product of 25 and 3

[tex]b = \sqrt{25*3}[/tex]

Split the expression

[tex]b = \sqrt{25} *\sqrt{3}[/tex]

[tex]b = \±5 *\sqrt{3}[/tex]

[tex]b = \±5 \sqrt{3}[/tex]

[tex]b = 5 \sqrt{3} \ or\ b = -5 \sqrt{3}[/tex]

The options are not clear enough; however the roots of the equation are [tex]b = 5 \sqrt{3} \ or\ b = -5 \sqrt{3}[/tex]