(a) There are $n$ chairs in a row. Find the number of ways of choosing $k$ of these chairs, so that no two chosen chairs are adjacent.


(b) There are 10 chairs in a circle, labelled from 1 to 10. Find the number of ways of choosing 3 of these chairs, so that no two chosen chairs are adjacent.


(c) There are $n$ chairs in a circle, labelled from 1 to $n.$ Find the number of ways of choosing $k$ of these chairs, so that no two chosen chairs are adjacent.

Answers

Answer 1

Answer:

(A) P (n,k) = n!/(n-k)! divided by 2

(B) C (n,3) = n!/(12)(n-3)!

(C) C (n,k) = n!/(n-k)!(k!)

Step-by-step explanation:

Permutation deals with order or arrangement or position of objects. Where this does not matter, we use the Combination formula.

We divide by 2 in all cases, because no 2 chosen chairs should be adjacent.

For (B), n=10

C (n,3) = n!/(n-3)!(3!) divided by 2

3! = 3×2×1 = 6

The expression divided by 2 means it will be multiplied by 1/2

Hence 6×2 = 12

And we arrive at

C (n,3) =n!/(12)(n-3)!


Related Questions

Solve for a.
ab + c = d

Answers

Answer:

a=(d-c)/d

Step-by-step explanation:

ab+c=d

ab=d-c

a= (d-c)/b

if f(x)=ln(sin(2x)), f''(π/4) is equal to​

Answers

Use the chain rule to compute the second derivative:

[tex]f(x)=\ln(\sin(2x))[/tex]

The first derivative is

[tex]f'(x)=(\ln(\sin(2x)))'=\dfrac{(\sin(2x))'}{\sin(2x)}=\dfrac{\cos(2x)(2x)'}{\sin(2x)}=\dfrac{2\cos(2x)}{\sin(2x)}[/tex]

[tex]f'(x)=2\cot(2x)[/tex]

Then the second derivative is

[tex]f''(x)=(2\cot(2x))'=-2\csc^2(2x)(2x)'[/tex]

[tex]f''(x)=-4\csc^2(2x)[/tex]

Then plug in π/4 for x :

[tex]f''\left(\dfrac\pi4\right)=-4\csc^2\left(\dfrac{2\pi}4\right)=-4[/tex]

A tank contains 60 kg of salt and 1000 L of water. A solution of a concentration 0.03 kg of salt per liter enters a tank at the rate 9 L/min. The solution is mixed and drains from the tank at the same rate. Let y be the number of kg of salt in the tank after t minutes. Write the differential equation for this situation

Answers

Answer:

[tex]\dfrac{dy}{dt}=0.27-0.009y(t),$ y(0)=60kg[/tex]

Step-by-step explanation:

Volume of water in the tank = 1000 L

Let y(t) denote the amount of salt in the tank at any time t.

Initially, the tank contains 60 kg of salt, therefore:

y(0)=60 kg

Rate In

A solution of concentration 0.03 kg of salt per liter enters a tank at the rate 9 L/min.

[tex]R_{in}[/tex] =(concentration of salt in inflow)(input rate of solution)

[tex]=(0.03\frac{kg}{liter})( 9\frac{liter}{min})=0.27\frac{kg}{min}[/tex]

Rate Out

The solution is mixed and drains from the tank at the same rate.

Concentration, [tex]C(t)=\dfrac{Amount}{Volume} =\dfrac{y(t)}{1000}[/tex]

[tex]R_{out}[/tex] =(concentration of salt in outflow)(output rate of solution)

[tex]=\dfrac{y(t)}{1000}* 9\dfrac{liter}{min}=0.009y(t)\dfrac{kg}{min}[/tex]

Therefore, the differential equation for the amount of Salt in the Tank  at any time t:

[tex]\dfrac{dy}{dt}=R_{in}-R_{out}\\\\\dfrac{dy}{dt}=0.27-0.009y(t),$ y(0)=60kg[/tex]

work out the weekly mean number of 50 kg bags of flour used in these 5 weeks

Kim is a baker, she buys flour in 50kg bags.
weeks 1 2 3 4

NO of bags of flour 7 14 8 13

Kim will make 2400 loaves in week 5
Each of these loaves will need 250g of lour

Kim works out weekly mean number of 50kg bags of flour used in these 5 weeks.
she will use the figure for future orders.

Answers

Answer:

Weekly Mean Number of 50-kg bags =10.8 bags

Step-by-step explanation:

In Week 1, Kim uses 7  50kg bags of flour

In Week 2, Kim uses 14  50kg bags of flour

In Week 3, Kim uses 8 X 50kg bags of flour

In Week 4, Kim uses 13 X 50kg bags of flour

In Week 5, Kim will make 2400 loaves.

Each of these loaves will need 250g of flour.

Total Mass of flour that will be used =2400 X 250=600,000 grams

[tex]600,000$ grams=600,000 \div 1000$ kg =600kg\\Number of 50-kg bags =600 \div$ 50 =12 bags[/tex]

In Week 5, Kim will use 12 bags.

Therefore:

Weekly Mean number of 50kg bags of flour used in these 5 weeks.

[tex]=\dfrac{7+14+8+13+12}{5}\\\\ =\dfrac{54}{5}\\\\=10.8 \\ \approx 11$ bags[/tex]

What else would need to be congruent to show that ABC=DEF by SAS?

Answers

Answer:

A

Step-by-step explanation:

Answer:

The answer here is A.

A) A is congruent to D.

A=

Step-by-step explanation:

AP E

A fast food hamburger restaurant uses 3,500 lbs. of hamburger each week. The manager of the restaurant wants to ensure that the meat is always fresh i.e. the meat should be no more than two days old on average when used. How much hamburger should be kept in the refrigerator as inventory

Answers

Answer:

The peak inventory will be 2 sales days of hamburguers, which is equivalent to 7,000 lbs. As they are consumed in 2 days, the average inventory is 3,500 lbs.

Step-by-step explanation:

If the meat should be no more than two days old on average when used, the stock of hamburguer in the refrigerator has to be at most the equivalent to 2 day of sales.

The "2 days old" represents the inventory turnover.

If we use all the hamburguers in the refrigerator and refill inmediatly, the average inventory is:

[tex]\bar I=\dfrac{\text{Beginning inventory}+\text{Ending inventory}}{2}\\\\\\\bar I=\dfrac{2*3,500+0}{2}=3,500[/tex]

The peak inventory will be 2 sales days of hamburguers, which is equivalent to 7,000 lbs. As they are consumed in 2 days, the average inventory is 3,500 lbs.

Each roll of tape is 30.5 feet long. A box contains 454 rolls of tape. How many yards are there in total

Answers

Answer:

Answer: 4615.66667

Steps: 1 foot=0.33333

total feets=30.5×454=13847

13847 feets=46.1566667 yards

Find the value of x.

Answers

Answer:

Step-by-step explanation:

so there’s 25 and 25 it’s kinda like counting money divide it into 4 pieces 25 , 50 , 75 , 100

Answer:

The answer would be x=3

Step-by-step explanation:

TIMED PLEASE HELP When f = 2 and g = 8, n = 4. If n varies jointly with f and g, what is the constant of variation?
1/4
1/2
4
64

Answers

The Answer is 1/4

Step-by-step explanation:

The required constant of variation for given data is k = 1/4

The correct option is (a)

What is constant of variation?

In a direct variation, the product of two variables; in an inverse variation, the ratio of two variables, is called constant of variation

Formula:

k = [tex]\frac{n}{fg}[/tex]

How calculate constant of variation?

Here we have given that n = 4, f = 2 and g = 8

Substitute the given values into above formula

k = [tex]\frac{4}{2(8)} =\frac{1}{4}[/tex]

The required constant of variation is 1/4

Therefore the correct option is (a)

This is the conclusion to the answer.

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Determine the number of ways three trumpet players out of 6 are chosen for 1st chair, 2nd chair, and 3rd chair.

Answers

Answer:

120 ways

Step-by-step explanation:

There are 3 spots and 6 options

_ _ _

1  2 3

6 ways for 1st chair to be chosen

5 ways for 2nd chair to be chosen (1st chair is chosen already, so there are 5 players left)

4 ways for 3rd chair to be chosen (1st and 2nd are already chosen, only 4 players left)

Multiply 6*5*4 to find the total number of ways (120)

Tamar rides her bike 960 feet in 2 minutes. What is her rate of speed?

Answers

Answer:

Rate of speed = 480 feet per minutes

Step-by-step explanation:

Given:

Distance covered by bike = 960 feet

Time taken to covered distance = 2 minutes

Find:

Rate of speed = ?

Computation:

⇒ Speed = Distance / Time

Rate of speed = Distance covered by bike / Time taken to covered distance

Rate of speed = 960 / 2

⇒ Rate of speed = 480 feet per minutes

Write an equation of a line that is parallel to the line 3y=-x+6 and passes through the point (6,2).

Answers

Answer:

y = x+2

y =-x+2  shows 0

We want to show 1 both sides

2y = x+2  shows 2

y = x+2 shows 0 as explained below.

Step-by-step explanation:

3y−x=6

Solve for y.

y=2+x3

Rewrite in slope-intercept form.

y=13x+2.

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

Slope: 13 y-intercept: 2

Any line can be graphed using two points. Select two

x values, and plug them into the equation to find the corresponding y values.

xy 02, 33

Graph the line using the slope and the y-intercept, or the points.

Slope:

13y-intercept: 2x y (0,2) (3,3)

please hurry I’ll make brainiest

A ball is tossed into the air from a height of 6 feet above ground level,
with a velocity of 3.4 feet per second. Which function could be used to
model the height of the ball, after t seconds?

Answers

Answer:

I think it would be the first but not 100% sure

Step-by-step explanation:

Tyson’s puppy weighed 8 pounds 3 ounces last year.
In one year the puppy gained 2 pounds 4 ounces.
How much does Tyson’s puppy weigh now in ounces?

Answers

Last year- 8 lbs 3 ounces

Add 2 lbs and 4 ounces

Which is 10 lbs 7 ounces

10 lbs in onces is 160 ounces

Then you add the other 7 ounces so the final answer is 167 ounces

Tyson’s puppy weighs 167 ounces!

Good luck please mark me as braniliest!!!!!!

Which of the following expressions shows the correct amount of sales tax for the computer at Store A? Select all that apply. 6%($1,200) 0.6($1,200) 0.06($1,200) 1/6($1,200) 3/50($1,200)

Answers

Answer:

1, 3,5

Step-by-step explanation:

Answer:

1,3,5

Step-by-step explanation:

Which graph shows exponential growth?

Answers

The answer is graph A 7/9/20 edge

Step-by-step explanation:

Answer:

a

Step-by-step explanation:

For a particular diamond mine, 78% of the diamonds fail to qualify as "gemstone grade". A random sample of 106 diamonds is analyzed. Find the mean μ.

Answers

Answer:

Mean of the binomial distribution  μ = 82.68

Step-by-step explanation:

Explanation:-

Given sample size 'n' = 106 diamonds

The probability that the diamonds fail to qualify as "gemstone grade

p = 78% =0.78

We will use binomial distribution

Mean of the binomial distribution

                                       μ = n p

                                       μ = 106 × 0.78

                                       μ = 82.68

conclusion:-

Mean of the binomial distribution  μ = 82.68

It’s a math riddle please help Id appreciate it I need this quickly I’ll give additional points... I’d do need an explanation because the question requires it.

Answers

The answer is 157
There are three cloaks, so you have to think, what times what equals 21? 7•3=21 after that you just do that formula through the rest 3•10=30
For the last one you have to figure what added and subtracting itself would equal 15? Well it would be 15
15+15-15=15
After that put it all together and you get 157
7+10•15=157
Hope that helps☀️

The puzzle are: 21, 30, 15, 333.

Puzzle

Clock:

Clock time=9 o'clock+9 o'clock+3 o'clock

Clock time=21

Calculator:

Calculator 1=1+2+3+4=10

Calculator 2=1+2+3+4=10

Calculator 3=1+2+3+4=10

Calculator=10+10+10

Calculator=30

Bulb:

The 3 bulb has 5 light each which represent the brightness of the 3 bulb.

Bulb=15+(15-15)

Bulb =15+0

Bulb=15

Fourth puzzle

Clock+Calculator×Bulb

9 o'clock+(1+2+2+4)× [3 bulb(3 bulb×4 light)]

9+9×(3×12)

Apply BODMAS

9+9×36

9+324

=333

Inconclusion the puzzle are: 21, 30, 15, 333.

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What’s the correct answer for this question?

Answers

Answer:

B:

Step-by-step explanation:

Measure of ARC AFB is 180°

Why?

This is because AB is a diameter.

B is the correct answer

g(-4)
Please help!!

Answers

Answer:

1

Step-by-step explanation:

g(-4) means what is the y value when x is -4.

Find x=-4, and when x=-4. y=1

Answer:

1

Step-by-step explanation:

Professional basketball coaches may coach at one of three levels: Assistant, Associate, or Head. It is possible to transition from any of these levels (states) to another. Each of these three states is transient because once someone leaves coaching at any level they never return (at least according to our model). On average, annual salary for head coaches is $104,485, for associates is $62,993, and for assistants is $41,389. Using our P matrix, we have solved to find the fundamental matrix (we have called it the (I-Q) inverse matrix): Assist Assoc Head Assist 6 4 2 Assoc 2 6 6 Head 1 2 10 For someone who is a head coach - what is their expected income for the remainder of their professional coaching career?

Answers

Answer:

For someone who is a head coach - their expected income for the remainder of their professional coaching career will be

Expected income = 1×$41,389 + 2×$62,993 + 10×$104,485

Expected income = $1,212,225

Step-by-step explanation:

Professional basketball coaches may coach at one of three levels:

AssistantAssociateHead

On average, the annual salary is given by

Assistant = $41,389Associate = $62,993Head = $104,485

Using our P matrix, we have solved to find the fundamental matrix (we have called it the (I-Q) inverse matrix):

                      Assistant      Associate     Head

Assistant              6                     4              2

Associate             2                     6              6        

Head                    1                      2              10

For someone who is a head coach - what is their expected income for the remainder of their professional coaching career?

As per the given P matrix, for someone who is a head coach will be:

Assistant = 1 time

Associate = 2 times

Head = 10 times

Therefore, the expected income will be,

Expected income = 1×$41,389 + 2×$62,993 + 10×$104,485

Expected income = $1,212,225

A plane intersects the prism perpendicular to the base, intersecting opposite sides of the base. Which best describes the cross section?

Answers

Answer:

Step-by-step explanation:

For a rectangular prism, a plane intersecting this prism produces a two dimensional figure as its cross section and in this case the cross section is a rectangle.

For a triangular prism, a plane intersecting this prism produces a two dimensional figure as its cross section and in this case the cross section is a triangle.

"The chance that a person selected at random has blue eyes is 16%. Two people are chosen at random (and are independent of each other). Find the probability at least one of them does not have blue eyes. Round your answer to 4 decimal places."

Answers

Answer:

[tex]P(X=0)=(2C0)(0.84)^0 (1-0.84)^{2-0}=0.0256[/tex]

And replacing we got:

[tex] P(X \geq 1)=1 -P(X<1) = 1-P(X=0)=1-0.0256=0.9744[/tex]

Step-by-step explanation:

Let X the random variable of interest, on this case we now that:

[tex]X \sim Binom(n=2, p=1-0.16=0.84)[/tex]

The probability mass function for the Binomial distribution is given as:

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

Where (nCx) means combinatory and it's given by this formula:

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

And we can find this probability:

[tex] P(X \geq 1)[/tex]

And we can solve this probability like this:

[tex] P(X \geq 1)=1 -P(X<1) = 1-P(X=0)[/tex]

And if we use the probability mass function we got:

[tex]P(X=0)=(2C0)(0.84)^0 (1-0.84)^{2-0}=0.0256[/tex]

And replacing we got:

[tex] P(X \geq 1)=1 -P(X<1) = 1-P(X=0)=1-0.0256=0.9744[/tex]

need answers to 34 35 and 36

Answers

Answer:

34) 75

35) 60

36) 210

Step-by-step explanation:

34) Area of a rectangle:

L x B

= 15 x 5

= 75

35) Area of a trapezium :

½ h (sum of || sides)

= ½ x 6 x (12+8)

= 3 x 20

= 60

36) Area of a regular hexagon:

3BH

= 3 x 7 x 10

210

Hope it helps....

Answer:

Step-by-step explanation:

35. 75

area of rectangle : A = b x h

                                  = 15 X 5

                                   = 75

36. 60

area of trapezoid : A = (b1 + b2) x h

                                                2

                                  = (8+12) x 6

                                            2

                                   = 60

37. 210

area of regular polygon : A = P x a  (P no. of sides) (a is apothem)

                                                   2

                                           = (6 x 10) x 7

                                                       2

                                           = 210

                       

                         

Write the equation of the line parallel to y+4= 1/4(x+5) and passing through the point (8, 20). Write in the format y = mx + b

Answers

Answer:

[tex]y=0.25x+18[/tex]

Step-by-step explanation:

So first we take the equation we are given and write it in slope-intercept form (y = mx + b):

[tex]y+4= \frac{1}{4} (x+5)\\\\y+4=0.25x +1.25\\\\y=0.25x-2.75[/tex]

Now we know parallel lines have the same slope, so the line we are looking for has a slope of 0.25.

so we can start to set up our equation:

[tex]y=0.25x+b[/tex]

and then substitue in the point (8,20) to find the y-intercept.

[tex]20=0.25(8)+b\\20=2+b\\b=18[/tex]

So now we have our equation:

[tex]y=0.25x+18[/tex]

Hope this helps!

The radius of a circle is 2.6 in. Find the circumference
to the nearest tenth.

Answers

Answer:

16.

Step-by-step explanation:

since given the radius and the formula of the circumference of a circle is 2pie*r

Please answer this correctly

Answers

Answer:

10 people

Step-by-step explanation:

Count the x's for more than 1 scarf, which is 2 or 3 scarfs

2 = 9

3 =1

total = 10

Liquid suspension contains 125 MG of medication aide for every 300 ML solution this is Spenton is being infused into a patient at the rate of 100 ML per hour if the infusion started at 6 AM and the patient needs 500 MG of the medication a at what time will you need to stop the infusion

Answers

Answer:

6 PM

Step-by-step explanation:

125 mg --- 300 mL

500 mg --- x mL

x = 500*300/125 = 1200 mL solution contains 500 mg

rate = 100 mL/h

1200 mL* 1h/100 mL = 12 h

6AM + 12 h = 6 PM

You need to stop infusion  at 6 PM

It is found that You need to stop infusion at 6 PM.

What is the unitary method?

The unitary method is a method for solving a problem by the first value of a single unit and then finding the value by multiplying the single value.

Given that Liquid suspension contains 125 MG of medication aide for every 300 ML solution this is Spenton is being infused into a patient at the rate of 100 ML per hour if the infusion started at 6 AM and the patient needs 500 MG of the medication.

125 mg = 300 mL

500 mg = x mL

x = 500*300/125

x = 1200 mL

Here solution contains 500 mg

The rate = 100 mL/h

1200 mL* 1h/100 mL = 12 h

6AM + 12 h = 6 PM

Therefore, You need to stop infusion at 6 PM.

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5.44 Teaching descriptive statistics: A study compared five different methods for teaching descriptive statistics. The five methods were traditional lecture and discussion, programmed textbook instruction, programmed text with lectures, computer instruction, and computer instruction with lectures. 45 students were randomly assigned, 9 to each method. After completing the course, students took a 1-hour exam. (a) What are the hypotheses for evaluating if the average test scores are different for the different teaching methods?

Answers

Answer:

The null hypothesis is that all the different teaching methods have the same average test scores.

H0: μ1 = μ2 = μ3 = μ4 = μ5

The alternative hypothesis is that at least one of the teaching methods have a different mean.

Ha: at least one mean is different. (μ1 ≠ μi)

Step-by-step explanation:

The null hypothesis (H0) tries to show that no significant variation exists between variables or that a single variable is no different than its mean. While an alternative Hypothesis (Ha) attempt to prove that a new theory is true rather than the old one. That a variable is significantly different from the mean.

For the case above, let μ represent the average test scores for the teaching methods:

The null hypothesis is that all the different teaching methods have the same average test scores.

H0: μ1 = μ2 = μ3 = μ4 = μ5

The alternative hypothesis is that at least one of the teaching methods have a different mean.

Ha: at least one mean is different. (μ1 ≠ μi)

What’s the correct answer for this question?

Answers

Answer:

107 meters

Step-by-step explanation:

Central angle = 123°

In radians

123° = 123π/180

123° = 2.147 radians

Putting in formula

S = r∅

S = (50)(2.147)

S = 107 meters

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She_______since morning The Polynesian people are considered to be descendants of the seafaring Austronesian people who themselves originated in the Malaysian region of Southeast Asia. Polynesia is a sub-region of Oceania, located just northeast of Australia and New Zealand. Although Polynesia is composed of over 1,000 islands, the people living on those islands share a similar culture, language, and ethnicity. Over 6,000 years ago, sailors and their families took to the seas in search of more lands. They scattered across the islands of the South Pacific. The process these people used to navigate is yet unknown to anthropologists. Samoa and Tonga are both American protectorates located in Polynesia; Hawaii is also located there.Which of these best states the author's purpose?A.) to persuade the reader take a trip to PolynesiaB.) to explain how the U.S. acquired its Pacific islandsC.) to entertain the reader with a Polynesian mythD.) to educate the reader about the Polynesian people Which of the following atoms has the largest atomic radius? Provide an explanationa Hydrogenb. SodiumC Lithiumd Rubidium Jill invested $20,000 in an account that earned 5.5% annual interest, compounded annually. What is the value of this account after 10 years? Express your answer rounded to the nearest cent. What is the domain of f(x) = 2|x 1| + 3? A. {x | x 3} B. {x | x < 1} C. {x | x -1} D. {x | x = all real numbers} Connor and Matthew each live in a different city. Each Thursday for ten weeks, they recorded the high temperature. The data below is the high temperature, in Fahrenheit, that they recorded. Connor's data: 50, 51, 50, 66, 60, 66, 71, 70, 72, 65, and 70. Matthew's data: 72, 82, 76, 84, 77, 73, 70, 67, 67, 56, and 65. What is the range of temperatures in Connor's data? What is X:3x22=445/6 = 10/2x3 An angle in standard position crosses the unit circle at (0, - 1). Which could be the angle measures? Please answer correctly !!!! Will mark brainliest answer !!!!!!!!! WRITE ANY THREE CHARACTERISTICS OF RABI, KHARIF AND ZAID CROPS ?. Help with some English just read the story then answer the questions What is one reason why we study properties of minerals?SCIENCE Is a measure of 22 inches "far away" from a mean of 16 inches? As someone with knowledge of statistics, you answer "it depends" and request the standard deviation of the underlying data. (a) Suppose the data come from a sample whose standard deviation is 2 inches. How many standard deviations is 22 inches from 16 inches? (b) Is 22 inches far away from a mean of 16 inches? (c) Suppose the standard deviation of the underlying data is 4 inches. Is 22 inches far away from a mean of 16 inches? Match the type of distribution map in column 1 with the information that kindof map will show in column 2.Linguisticdistribution map?Population density indifferent parts of aterritoryEthnicdistribution map?Ethnic divisions anddiversity in a territoryPopulationdistribution map?Places where differentreligions dominateReligiousdistribution map2.The location of speakersof various languages Software that interprets commands from the keyboard and mouse is also know as the A water cooler holds 15 liters of sports drink. Approximately how many gallons is this (X+3)/6=5/4 what is x Which of the following is Tj length of GF given that figure DEFG is parallelogram?Plz help A well diversified portfolio needs about 3 to 5 stocks from different categories.TrueFalse Help me quick please