I don’t understand these 3 questions and I need help.

Answer:

By the Central Limit Theorem, the distribution of the sample means is approximately normal with mean 41 and standard deviation 2.92, in thousands of dollars.

Step-by-step explanation:

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.

Mean of 41, standard deviation of 28:

This means that [tex]\mu = 41, \sigma = 28[/tex]

Sample of 92:

This means that [tex]n = 92, s = \frac{28}{\sqrt{92}} = 2.92[/tex]

Distribution of the sample means:

By the Central Limit Theorem, the distribution of the sample means is approximately normal with mean 41 and standard deviation 2.92, in thousands of dollars.

Answer:

[tex]G(t) = 120e^{-0.0257t}[/tex]

Step-by-step explanation:

Amount of substance:

The amount of the substance after t minutes is given by:

[tex]G(t) = G(0)e^{-kt}[/tex]

In which G(0) is the initial amount and k is the decay rate.

At the beginning of an experiment, a scientist has 120 grams of radioactive goo.

This means that [tex]G(0) = 120[/tex], so:

[tex]G(t) = G(0)e^{-kt}[/tex]

[tex]G(t) = 120e^{-kt}[/tex]

After 135 minutes, her sample has decayed to 3.75 grams.

This means that [tex]G(135) = 3.75[/tex].

We use this to find k. So

[tex]G(t) = 120e^{-kt}[/tex]

[tex]3.75 = 120e^{-135k}[/tex]

[tex]e^{-135k} = \frac{3.75}{120}[/tex]

[tex]\ln{e^{-135k}} = \ln{\frac{3.75}{120}}[/tex]

[tex]-135k = \ln{\frac{3.75}{120}}[/tex]

[tex]k = -\frac{\ln{\frac{3.75}{120}}}{135}[/tex]

[tex]k = 0.0257[/tex]

So

[tex]G(t) = 120e^{-0.0257t}[/tex]

Answer:

dC=3.5

DC is between 3.475 and 3.525

Step-by-step explanation:

So let dx=1 since the change there is a change in 1 unit.

Find dC/dx by differentiating the expression named C.

dC/dx=0.05x+3

So dC=(0.05x+3) dx

Plug in x=10 and dx=1:

dC=(0.05×10+3)(1)

dC=(0.5+3)

dC=3.5

Let D be the change in cost-the triangle thing.

Since dx=1 we only want the change in unit to be within 1 in difference.

So this means we want it to be from x=9 to x=1] ot from x=10 to x=11.

Let's do from x=9 to x=10 first:

DC=C(10)-C(9)

DC=[0.025×10^2+3×10+4]-[0.025×9^2+3×9+4]

DC=[2.5+30+4]-[0.025×81+27+4]

DC=[36.5]-[2.025+31]

DC=[36.5]-[33.025]

DC=3.475

Now let's do from x=10 to x=11

DC=[0.025×11^2+3×11+4]-[0.025×10^2+3×10+4]

DC=[0.025×121+33+4]-[36.5]

DC=[3.025+37]-[36.5]

DC=[40.025]-[36.5]

DC=3.525

So DC, the change in cost where the change in unit is 1, is between 3.475 and 3.525.

Answer:

A.

Step-by-step explanation:

The Elimination Method is the method for solving a pair of linear equations which reduces one equation to one that has only a single variable.

If the coefficients of one variable are opposites, you add the equations to eliminate a variable, and then solve.

If the coefficients are not opposites, then we multiply one or both equations by a number to create opposite coefficients, and then add the equations to eliminate a variable and solve.

When multiplying the equation by a coefficient, we multiply both sides of the equation (multiplying both sides of the equation by some nonzero number does not change the solution).

So, option B is not allowed (it is not allowed to multiply only one part of the equation)

Answer:

D is your answer

Step-by-step explanation:

Answer:

Here the slope formula m = ( y 2 − y 1 )/( x 2 -x 1 ) = Δy/Δx

Step-by-step explanation:

Answer:

B is the answer

Step-by-step explanation:

Answer:

B

Step-by-step explanation:

you would have to multiply 2000 and the 25 and then divide

Step-by-step explanation:

(-2,-1,0,3,4) are the domain

(x,y)=(domain,range)

simply x components are the domain whereas y components are the range

Step-by-step explanation:

the answer is in the image above

Answer:

A' (- 1, - 5 )

Step-by-step explanation:

Under a counterclockwise rotation about the origin of 90°

a point (x, y ) → (- y, x ), then

A (- 5, 1 ) → A' (- 1, - 5 )

Answer:

Amount of sales

Step-by-step explanation:

The dependent variable also called the measured or predicted variable is simply the variable obtained due to inputs in of the independent variable. It is the variable which is being measured in an experiment. Here, the test is that the number of sales depends on the number of contact. Here, the number of contacts will has an influence or determines the amount of sales, hence, the number of contacts is the independent variable while the amount of sales is the dependent variable.

Answer:

she can make 12 sandwiches

Step-by-step explanation:

3/.25 is the solution

Answer:

Step-by-step explanation:

The following configured particulars are states, in accordance by the interrogate:

Perimeter = 96 hectometers.

Assuming the figure is a square, we can assume that,

S = A side length where,

4s = 96, where all side lengths are equivalent.

If so, then s = 24

Thus, that means that w, denoted as width, must be less than or equal to 24.

In addition, likewise, l, denoted as length, must be less than or equal to 24.

Furthermore, the length is acknowledged or stated to be twice that of the width:

Length = 2w

The listed above may be equated to the following:

2w + 2L = 96

2(24) + 2L = 96

2L + 48 = 96

2L = 48

L = 24

Thus, the width of the figure is equivalent to 24. (Length divided by two).

Thus, the length of the figure is equivalent to 24 (twice the width).

*I hope this helps.

Answer:

5000 ;

11125

Step-by-step explanation:

Given :

Total principal = 16125

Rates = 8.5% and 4%

Period, t = 2 years

Total interest = 1740

Let :

Principal amount invested at 8.5% = x

Principal amount invested at 4% = 16125 - x

Interest formula :

Interest = principal * rate * time

Hence, mathematically ;

(x * 8.5% * 2) + [(16125 - x) * 4% * 2] = 1740

(0.17x + 1290 - 0.08x ) = 1740

0.09x + 1290 = 1740

0.09x = 1740 - 1290

0.09x = 450

x = 450 / 0.09

x = 5000

Amount invested at 4% :

16125 - 5000 = 11125

Answer

The Answer is A C D

Step-by-step explanation:

Answer:

[tex]y = 6x - 60[/tex] --- formula

The stopping distance at 40mph is 180ft

Step-by-step explanation:

Given

[tex](x,y) = (20,60)[/tex]

[tex](x,y) = (30,120)[/tex]

Solving (a): Construct a formula

Calculate the slope (m)

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

[tex]m = \frac{120 - 60}{30-20}[/tex]

[tex]m = \frac{60}{10}[/tex]

[tex]m=6[/tex]

So, the equation is:

[tex]y = m(x - x_1) + y_1[/tex]

[tex]y = 6(x - 20) + 60[/tex]

Open bracket

[tex]y = 6x - 120 + 60[/tex]

[tex]y = 6x - 60[/tex]

Hence, the formula to use is: [tex]y = 6x - 60[/tex]

Solving (b): y, when x = 40

[tex]y = 6x - 60[/tex]

[tex]y = 6 * 40 - 60[/tex]

[tex]y = 180[/tex]

Answer:

61600

Step-by-step explanation:

the 3rd digit is the hundreds. because the digit in the 10s is greater 5, we round it up

Answer:

61,600 is your answer please

Answer:

B.End behavior

Step-by-step explanation:

Limit as x goes to infinity:

To find the limit as x goes to infinity of a function, we consider only the leading coefficient and the term with the highest degree of the polynomial, and this limits determines the end behavior of a function, and thus, the correct answer is given by option b.

Answer:

a. negative

b. negative

c. positive

Step-by-step explanation:

a. When a negative and positive integer are being multiplied the product will always be negative. For example, -3*2=-6.

b. Before answering this question it is helpful to realize that it is the exact same as part a. This is because the commutative property states that order does not matter in multiplication. So the answer is also negative, 2*-3=-6.

c. If two negative integers are multiplied then the product will be positive. Whenever two integers of the same sign are multiplied the product is positive. The opposite is true when they have different signs; the product will always be negative. An example of two negative integers would be -3*-2=6.

Answer:

Pie( r ^2)

Step-by-step explanation:

Here value of r is in inches

Answer: B. Right Scalene

Step-by-step explanation: Right because one of the degrees is 90 and scalene because no of the sides of the triangle are the same length.

Answer:

b

Step-by-step explanation:

Answer:

An expression is considered simplified only if there is no radical sign in the denominator. If we do have a radical sign, we have to rationalize the denominator . This is achieved by multiplying both the numerator and denominator by the radical in the denominator.

Answer:

44

Step-by-step explanation:

Given that Avi used 11 toothpicks to form a row of 5 attached triangles.

Total number of toothpicks used = 89

Let the total number of triangles formed be represented by x, so that:

11 toothpicks = 5 triangles

It would be observed that only the first triangle starting the pattern has 3 toothpicks. So that;

the average number of toothpicks for 1 triangle = [tex]\frac{11}{5}[/tex]

                                  = 2.2

The number of toothpicks per triangle = 2.0

Thus,

x = [tex]\frac{89}{2.0}[/tex]

  = 44.5

x = 44

The total number of triangles formed is 44.

Answer:

D:20

sqrt(3) is less than 2 thus 10*sqrt(3) is less than 20

Step-by-step explanation:

Answer:

[tex]P(HH\ u\ C) = \frac{13}{16}[/tex]

Step-by-step explanation:

Given

The Venn diagram

Required

[tex]P(HH\ u\ C)[/tex]

This is calculated as:

[tex]P(HH\ u\ C) = \frac{n(HH\ u\ C)}{n(U)}[/tex]

Where:

[tex]n(U) = 16[/tex] --- count of students

[tex]n(HH\ u\ C) =13[/tex]

So, we have:

[tex]P(HH\ u\ C) = \frac{n(HH\ u\ C)}{n(U)}[/tex]

[tex]P(HH\ u\ C) = \frac{13}{16}[/tex]

9514 1404 393

Answer:

2. On a coordinate plane, a hyperbola is shown. One curve opens up and to the right in quadrants 1 and 4, and the other curve opens up and to the left in quadrants 2 and 3

Step-by-step explanation:

Technically, the curve is not a hyperbola. A hyperbola is of the form 1/x; this one is of the form 1/x².

The function can be simplified to ...

  f(x) = 5/x² -5

which is a "hyperbola" with a vertical asymptote at x=0 and a vertical translation of -5 units to bring parts of it into the 3rd and 4th quadrants.

9514 1404 393

Answer:

  Every night

Step-by-step explanation:

The problem statement tells you ...

  "Every night Chris reads a number of pages that can be rounded to the nearest hundred."

Then it asks you ...

  "On what nights does Chris read a number of pages that can be rounded to the nearest hundred?"

If we take the problem statement at face value, the answer must be ...

  "Every night."

Answer:

a) 0.4219 = 42.19% probability that one out of the next four cars needs oil.

b) 0.3115 = 31.15% probability that two out of the next eight cars needs oil.

c) 0.2581 = 25.81% probability that three out of the next 12 cars need oil.

Step-by-step explanation:

For each car, there are only two possible outcomes. Either they need oil, or they do not need it. The probability of a car needing oil is independent of any other car, which means that the binomial probability distribution is used to solve this question.

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.

One out of four cars needs to have oil added.

This means that [tex]p = \frac{1}{4} = 0.25[/tex]

a. One out of the next four cars needs oil.

This is P(X = 1) when n = 4. So

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

[tex]P(X = 1) = C_{4,1}.(0.25)^{1}.(0.75)^{3} = 0.4219[/tex]

0.4219 = 42.19% probability that one out of the next four cars needs oil.

b. Two out of the next eight cars needs oil.

This is P(X = 2) when n = 8. So

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

[tex]P(X = 2) = C_{8,2}.(0.25)^{2}.(0.75)^{6} = 0.3115[/tex]

0.3115 = 31.15% probability that two out of the next eight cars needs oil.

c.Three out of the next 12 cars need oil.

This is P(X = 3) when n = 12. So

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

[tex]P(X = 3) = C_{12,3}.(0.25)^{3}.(0.75)^{9} = 0.2581[/tex]

0.2581 = 25.81% probability that three out of the next 12 cars need oil.

Answer:

D. 31.5 sq. units

Step-by-step explanation:

The area of a triangle is

A = 1/2 bh

A = 1/2 ( 9)(7)

A = 63/2

A = 31.5 units^2

Step-by-step explanation:

For this, we'll use a formula for the area of a triangle.

Area (A) = ( Base (B) * Height (H) ) / 2

[tex]A = (B * H )/2[/tex]

[tex]A = (9*7)/2[/tex]

[tex]A = (63)/2[/tex]

[tex]A = 31.5[/tex]

Answer:

D. 31.5 sq. units

Answer:

The first option

Step-by-step explanation:

A function is where one input only has one output, in the other options we can see inputs having different outputs, 0,3 and 0-3 in the second and in the third -2,4 and -2,0.