There are 40 children in a classroom and n of them do not wear spectacles. (4)/(5) of the boys and (2)/(3) of the girls wear spectacles. Express the number of boys who wear spectacles in terms of n.

Answer:

a) 0.0808 = 8.08% probability that the sample mean rent is greater than $2700.

b) 0.0546 = 5.46% probability that the sample mean rent is between $2450 and $2550.

c) The 25th percentile of the sample mean is of $2596.

d) |Z| = 0.3 < 2, which means it would not be unusual if the sample mean was greater than $2645.

e) |Z| = 0.3 < 2, which means it would not be unusual if the sample mean was greater than $2645.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal Probability Distribution

Problems of normal distributions can be solved using the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:

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

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

If |Z|>2, the measure X is considered unusual.

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

The mean monthly rent for a one-bedroom apartment without a doorman in Manhattan is $2630. Assume the standard deviation is $500.

This means that [tex]\mu = 2630, \sigma = 500[/tex]

Sample of 100:

This means that [tex]n = 100, s = \frac{500}{\sqrt{100}} = 50[/tex]

a) What is the probability that the sample mean rent is greater than $2700?

This is the 1 subtracted by the p-value of Z when X = 2700. So

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

By the Central Limit Theorem

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

[tex]Z = \frac{2700 - 2630}{50}[/tex]

[tex]Z = 1.4[/tex]

[tex]Z = 1.4[/tex] has a p-value 0.9192

1 - 0.9192 = 0.0808

0.0808 = 8.08% probability that the sample mean rent is greater than $2700.

b) What is the probability that the sample mean rent is between $2450 and $2550?

This is the p-value of Z when X = 2550 subtracted by the p-value of Z when X = 2450.

X = 2550

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

[tex]Z = \frac{2550 - 2630}{50}[/tex]

[tex]Z = -1.6[/tex]

[tex]Z = -1.6[/tex] has a p-value 0.0548

X = 2450

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

[tex]Z = \frac{2450 - 2630}{50}[/tex]

[tex]Z = -3.6[/tex]

[tex]Z = -3.6[/tex] has a p-value 0.0002

0.0548 - 0.0002 = 0.0546.

0.0546 = 5.46% probability that the sample mean rent is between $2450 and $2550.

c) Find the 25th percentile of the sample mean.

This is X when Z has a p-value of 0.25, so X when Z = -0.675.

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

[tex]-0.675 = \frac{X - 2630}{50}[/tex]

[tex]X - 2630 = -0.675*50[/tex]

[tex]X = 2596[/tex]

The 25th percentile of the sample mean is of $2596.

Question d and e)

We have to find the z-score when X = 2645.

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

[tex]Z = \frac{2645 - 2630}{50}[/tex]

[tex]Z = 0.3[/tex]

|Z| = 0.3 < 2, which means it would not be unusual if the sample mean was greater than $2645.

Answer:

y= -3x +40

Step-by-step explanation:

Properties of perpendicular bisector:

• perpendicular to the given line

• cuts through the center of the given line

The equation of a line can be written in the form of y=mx +c, where m is the gradient and c is the y -intercept.

Let's find the gradient of the given line first.

[tex]\boxed{gradient = \frac{y1 - y2}{x1 - x2} }[/tex]

Gradient of given line

[tex] = \frac{6 - 2}{18 - 6} [/tex]

[tex] = \frac{4}{12} [/tex]

[tex] = \frac{1}{3} [/tex]

The product of the gradients of perpendicular lines is -1.

m(⅓)= -1

m= -1(3)

m= -3

Substitute m= -3 into the equation:

y= -3x +c

To find the value of c, substitute a pair of coordinates in which the perpendicular bisector passes through into the equation. Since perpendicular bisectors passes through the center of the segment, we can find the point in which the perpendicular bisector passes through using the mid- point formula.

[tex]\boxed{midpoint = ( \frac{x1 + x2}{2} , \frac{y1 + y2}{2} )}[/tex]

Midpoint

[tex] = ( \frac{6 + 18}{2} , \frac{6 + 2}{2} )[/tex]

[tex] = ( \frac{24}{2} , \frac{8}{2} )[/tex]

[tex] = (12,4)[/tex]

y= -3x +c

when x= 12, y= 4,

4= -3(12) +c

4= -36 +c

c= 4 +36

c= 40

Thus, the equation of the perpendicular bisector is y= -3x +40.

Answer:

Variance = 3.6 voteres

Step-by-step explanation:

Probability of favour voters, P = 0.22

Total number of voters, n = 21

The probability of voters who are in not favour of new hospital construction = 1  - P

The probability of voters who are in not favour of new hospital construction = 1  - 0.22

The probability of voters who are in not favour of new hospital construction, P* = 0.78

Variance = n x p* x (1 - p*)

Variance = 21 x 0.78 x 0.22

Variance = 3.6 voters

Answer:

the slope-intercept form for any line is y = mx + b, where m is the slope and b is the y-intercept.

now, let's calculate the slope:

=  

here is the equation we currently have solved: y = x + b

now we have to solve for the y-intercept. to do this, we substitute one of the given points into the equation, and solve for b.

let's use (8, 2). in this ordered pair, the 8 is the x, and the 2 is the y.

2 = 8 + b

2 - 8 = b

b = -6

and now we have our final equation!  

y = x - 6

hope this helped! please let me know if you are confused about anything i did smiley

Step-by-step explanation:

Answer:

Step-by-step explanation:

Find the slope first:

Use point-slope form and the coordinates of one of the points:

Answer:

The radius of the can, in centimeters, is of [tex]4\sqrt{5}[/tex]

Step-by-step explanation:

Radius of the can:

The radius of the can is given by:

[tex]r^2 = \frac{V}{h\pi}[/tex]

In which V is the volume and h is the height.

In this question:

[tex]V = 1280\pi, h = 16[/tex]

Thus

[tex]r^2 = \frac{V}{h\pi}[/tex]

[tex]r^2 = \frac{1280\pi}{16\pi}[/tex]

[tex]r^2 = 80[/tex]

[tex]r = \sqrt{80}[/tex]

[tex]r = \sqrt{5*16}[/tex]

[tex]r = \sqrt{5}\sqrt{16}[/tex]

[tex]r = 4\sqrt{5}[/tex]

The radius of the can, in centimeters, is of [tex]4\sqrt{5}[/tex]

Answer:

-( cube root of 2x)-6(cube root of x)

Answer:

7, 8, 9, 10, 11

Step-by-step explanation:

7+8+9+10+11

7 + 8 = 15

15 + 9 = 24

24 + 10 = 34

34 + 11 = 45

Answer:

[tex]x=-\frac{15}{382}[/tex]

Step-by-step explanation:

32 × 12x + 1 = 2x - 14

384x + 1 = 2x - 14

384x + 1 - 1 = 2x - 14 - 1

384x = 2x - 15

384x - 2x = 2x - 2x - 15

382x = - 15

382x ÷ 382 = - 15 ÷ 382

[tex]x=-\frac{15}{382}[/tex]

8 < x < 8.5 is your answer

other sides has to always be less than the hypotenuse

9514 1404 393

Answer:

  0.5 < x < 16.5

Step-by-step explanation:

The sum of the two shortest sides of a triangle must always exceed the length of the longest side.

If x and 8.0 are the short sides, then ...

  x + 8.0 > 8.5

  x > 0.5

If 8.0 and 8.5 are the short sides, then ...

  8.0 +8.5 > x

  16.5 > x

So, for the given triangle to exist, we must have ...

  0.5 < x < 16.5

_____

Additional comment

You will notice that the value 0.5 is the difference of the given sides, and 16.5 is their sum. This will always be the case for a problem like this. The third side length always lies between the difference and the sum of the other two sides.

Answer:

0.6826 = 68.26% probability Z will be within one standard deviation of average.

Step-by-step explanation:

Normal Probability Distribution

Problems of normal distributions can be solved using the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:

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

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

What is the probability Z will be within one standard deviation of average?

This is the p-value of Z = 1 subtracted by the p-value of Z = -1.

Z = 1 has a p-value of 0.8413.

Z = -1 has a p-value of 0.1587.

0.8413 - 0.1587 = 0.6826

0.6826 = 68.26% probability Z will be within one standard deviation of average.

Answer:

20%

Step-by-step explanation:

if zero toppings is an option, then there would be 5 possibilities for toppings

0,1,2,3,or 4

the server randomly chose 3 toppings so that would be one out of 5 or 20%.

(If the server did not have the option to put zero toppings on then there would be only 4 options 1,2,3, or 4 toppings and the correct answer would be one out of 4 or 25%.)

Answer:

0.5665 = 56.65% probability of less than four twos.

Step-by-step explanation:

For each roll, there are only two possible outcomes. Either it is a two, or it is not a two. The probability of a roll ending up in a two is independent of any other roll, which means that the binomial probability distribution is used.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.

[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]

And p is the probability of X happening.

A die is rolled 20 times

This means that [tex]n = 20[/tex]

One out of six sides is 2:

This means that [tex]p = \frac{1}{6} = 0.1667[/tex]

Probability of less than four twos:

This is:

[tex]P(X < 4) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3)[/tex]

So

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

[tex]P(X = 0) = C_{20,0}.(0.1667)^{0}.(0.8333)^{20} = 0.0261[/tex]

[tex]P(X = 1) = C_{20,1}.(0.1667)^{1}.(0.8333)^{19} = 0.1043[/tex]

[tex]P(X = 2) = C_{20,2}.(0.1667)^{2}.(0.8333)^{18} = 0.1982[/tex]

[tex]P(X = 3) = C_{20,3}.(0.1667)^{3}.(0.8333)^{17} = 0.2379[/tex]

So

[tex]P(X < 4) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) = 0.0261 + 0.1043 + 0.1982 + 0.2379 = 0.5665[/tex]

0.5665 = 56.65% probability of less than four twos.

Answer:

17/15

Step-by-step explanation:

6/5 * 17/18

1/5 * 17/3

17/15

Answer:

see below

Step-by-step explanation:

a) (– 3, –2) and (–3, 4)

First you want to find the slope of the line that passes through these points. To find the slope of the line, we use the slope formula: (y₂ - y₁) / (x₂ - x₁)

Plug in these values:

(4 - (-2) / (-3 - (-3))

Simplify the parentheses.

= (4 + 2) / (-3 + 3)

Simplify the fraction.

(6) / (0)

= undefined

If your slope is undefined, it is a vertical line. The equation of a vertical line is x = #.

In this case, the x-coordinate for both points is -3.

Therefore, your equation is x = -3.

b) (3, 2) and (–4, –5)

First you want to find the slope of the line that passes through these points. To find the slope of the line, we use the slope formula: (y₂ - y₁) / (x₂ - x₁)

Plug in these values:

(-5 - 2) / (-4 - 3)

Simplify the parentheses.

= (-7) / (-7)

Simplify the fraction.

-7/-7

= 1

This is your slope. Plug this value into the standard slope-intercept equation of y = mx + b.

y = 1x + b or y = x + b

To find b, we want to plug in a value that we know is on this line: in this case, I will use the first point (3, 2). Plug in the x and y values into the x and y of the standard equation.

2 = 1(3) + b

To find b, multiply the slope and the input of x(3)

2 = 3 + b

Now, subtract 3 from both sides to isolate b.

-1 = b

Plug this into your standard equation.

y = x - 1

This is your equation.

Check this by plugging in the other point you have not checked yet (-4, -5).

y = 1x - 1

-5 = 1(-4) - 1

-5 = -4 - 1

-5 = -5

Your equation is correct.

Hope this helps!

Answer:

y = 2x + 12

Step-by-step explanation:

the formula for a line is typically

y = ax + b

a is the slope of the line (expressed as y/x ratio describing how many units y changes, when x changes a certain amount of units).

b is the offset of the line in y direction (for x=0).

we have the points (3, -4) and (-7, 1).

to get the slope of the line let's wander from left to right (x direction).

to go from -7 to 3 x changes by 10 units.

at the same time y changes from 1 to -4, so it decreases by 5 units.

so, the slope is -5/10 = -1/2

and the line equation looks like

y = -1/2 x + b

to get b we simply use a point like (3, -4)

-4 = -1/2 × 3 + b

-4 = -3/2 + b

-5/2 = b

so, the full line equation is

y = -1/2 x - 5/2

now, for a perpendicular line the slope exchanges x and y and flips the sign.

in our case this means +2/1 or simply 2.

so, the line equation for the perpendicular line looks like

y = 2x + b

and to get b we use the point we know (-2, 8)

8 = 2×-2 + b

8 = -4 +b

12 = b

so, the full equation for the line is

y = 2x + 12

Answer:

2x-y+12= 0 or y = 2x+12 is the answer

Step-by-step explanation:

slope of the line joining (3,-4) and (-7,1) is 1-(-4)/-7-3

= -5/10

= - 1/2

slope of the line containing (-2,8) and that is perpendicular to the line containing (3,-4) and (-7,1) = 2

Equation of the line line containing (-2,8) and that is perpendicular to the line containing (3,-4) and (-7,1) is y-8 = 2(x-(-2))

y-8 = 2(x+2)

y- 8 = 2x+4

y=2x+12 (slope- intercept form) or 2x-y+12= 0 (point slope form)

Answer:

x^2+y^2=1

Step-by-step explanation:

Since cos^2(x)+sin^2(x)=1, x^2+y^2=1

Answer:

its 1900 Bc. Because BC stand for before chirst

Step-by-step explanation:

Answer:

The choose (2)

y=x²+5x+6

Step-by-step explanation:

y=x²+5x+6 —> (–5/2 , –1/4)

y=-3x² + 5 X + 6 —> (5/6, 97/12)

y=-x² + 5x + 6 —> (5/2,49/4)

y = -4 x² + 5x + 6 —> (5/8 , 121/16)

9514 1404 393

Answer:

  below

Step-by-step explanation:

When signed numbers are used to represent elevation with respect to sea level, positive signs are used for values above sea level, and negative signs are used for values below sea level. The given elevation of Death Valley indicates it is 282 feet below sea level.

Answer:

v nnv vb n

Step-by-step explanation:

b ng chfxhc.jx.gc,fhxfgfdkhgvn gghcjfuoctykfd mmyegfiuegfypgerukf khergfuoegrfyurgfirge jgreuyofrgiregvoifgr riygfepiygfreu;k frugfyrfbhrevf rrgfbreuobghfre rgeuherhbgerui freurehuregh ruogysfhurgiugwhlerghre rgiuyrge97grukbgr ker ruipuhrgeugregariyarga ;rskfglfsglgsfuifgryrgljs kjger;ugiergs hope this was helpful good luck!

Step-by-step explanation:

[tex] \frac{ \frac{6}{7} }{ \frac{9}{14} } [/tex]

[tex] = \frac{6}{7} \times \frac{14}{9} [/tex]

[tex] = \frac{2}{1} \times \frac{2}{3} [/tex]

[tex] = \frac{4}{3} = 1 \frac{1}{3} (Ans) [/tex]

[tex] \frac{18}{x} = \frac{6}{10} [/tex]

[By cross multiplication]

=> 18 × 10 = 6 × x

[tex] = > \frac{18 \times 10}{6} = x[/tex]

=> 3 × 10 = x

=> x = 30 (Ans)

Answer:

Pertaining to the mathematical expression conveyed, the answer to such proposed interrogate is acknowledged as the following:

Degree: 2nd degree term.

Classification: Quadratic trionomial.

Step-by-step explanation:

Evaluating the Degree:

The degree is acknowledged as the predominating term adjacent to a base of a peculiar value that denotes the particular allocation within a polynomial.

4x^2 has the highest degree of 2.

32x has the degree of one, being that x individually is x^1.

Since polynomials are defined by the term in which obtains the greatest degree, ^2 is referred to as quadratic, whereas ^3 is cubic, ^4…

Classification Evaluation:

Such could be determined by evaluating for the quantity of terms present within the mathematical expression or statement.

4x^2 is the first term.

32x is the second term.

63 is the third term (considered a constant).

Thus, the correct answer is a quadratic trinomial.

*I hope this helps.

[tex]\huge\textsf{Hey there!}[/tex]

[tex]\large\textsf{6!}\\\large\textsf{= 6}\times\large\textsf{5}\times\large\textsf{4}\times\large\textsf{3}\times\large\textsf{2}\times\large\textsf{1}\\\large\textsf{6(5) = \bf 30}\\\large\textsf{= 30}\times\large\textsf{4}\times\large\textsf{3}\times\large\textsf{2}\times\large\textsf{1}\\\large\textsf{30(4) = \bf 120}\\\large\textsf{= 120}\times\large\textsf{3}\times\large\textsf{2}\times\textsf{1}\\\large\textsf{120(3) = \bf 360}\\\large\textsf{= 360}\times\large\textsf{2}\times\large\textsf{1}[/tex]

[tex]\large\textsf{360(2) = \bf 720}\\\large\textsf{720}\times\large\textsf{1}\\\large\textsf{= \bf 720}[/tex]

[tex]\boxed{\boxed{\huge\textsf{Therefore, your answer is: \bf 720}\huge\textsf{ (option B)}}}\huge\checkmark[/tex]

[tex]\large\textsf{Good luck on your assignment and enjoy your day!}[/tex]

~[tex]\frak{Amphitrite1040:)}[/tex]

Answer:

7/0

Step-by-step explanation:

This is because if a number is divided by 0 then there is no answer or it is undefined

Think of it like this,

You have 7 apples and wanted to give it to zero friends, is it possible?

Hope this helped :)

Answer:

Second option (7÷0)

Explanation:

Dividing by zero is considered undefined since you can't divide something by nothing. It's like saying you have a pizza and you want to divide it between 7 people but since you're dividing by zero, you're not splitting the pizza between anyone.

9514 1404 393

Answer:

  x ∈ {-35, 0, 35}

Step-by-step explanation:

We can solve for x and equate those values to find corresponding y-values. Substituting into the original expressions for x gives the possible x-values.

  [tex]x+xy^2=250y\ \Rightarrow\ x=\dfrac{250y}{1+y^2}\\\\x-xy^2=-240y\ \Rightarrow\ x=\dfrac{-240y}{1-y^2}\\\\\dfrac{250y}{1+y^2}+\dfrac{240y}{1-y^2}=0\\\\\dfrac{25y(1-y^2)+24y(1+y^2)}{(1+y^2)(1-y^2)}=0\\\\y(-y^2+49)=0=y(7-y)(7+y)\ \Rightarrow\ y\in\{-7,0,7\}\\\\x=\dfrac{250(\pm 7)}{1+(\pm7)^2}=\pm35,\quad=\dfrac{250(0)}{1+0^2}=0\\\\\boxed{x\in\{-35,0,35\}}[/tex]

Answer:

[tex]-29.5-\frac{38}{15}x[/tex]

Step-by-step explanation:

First, we must expand out the -5.

-5 times 2/3x is equal to -10/3x, and -5 times 6 is equal to -30. 1/2 minus 30 is equal to -29.5, and 4/5x minus 10/3x is equal to -38/15x.

Answer:

A

Step-by-step explanation:

Slope = term that multiply x

y intercept = the number without a variable

Answer:

4s-9t-7

Step-by-step explanation:

multiply the negative one with all terms inside the bracket, since they are all unlike terms the answer remains the same