If ten people shake hands with each other exactly once, how many handshakes take place?

Answers

Answer 1

Apply the formula:

n(n+1)/2

Where n is the number of shake hands of the first person (9)

9 (9+1) /2

9 (10)/2

90/2

45 shakes


Related Questions

247474647447x4747474747

Answers

Answer:

1174879639277360520909 in exact form

or

in decimal form 1.17487963 x 10^21

Step-by-step explanation:

Suppose you are choosing at random from the numbers 1 through 12 (inclusive). If the event E is "the number is even," find the set representing E. Express your answer as a bracketed set in the form {a,b,c,d}.

Answers

The set numbers from 1 to 12(inclusive) is:

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12

The set even numbers are:

2, 4, 6, 8, 10, 12

Given that the event E is "the number is even"

Therefore, the set representing the event E as a bracketed set is:

[tex]E=\mleft\lbrace2,4,6,8,10,12\mright\rbrace[/tex]

2. (5 points) A very special island is inhabited only by knights and knaves. Knights always tell
the truth, and knaves always lie. You meet two inhabitants: Sue and Marge. Sue says that
Marge is a knave. Marge claims. "Sue and I are not the same." Determine who is a knight and
who is a knave.

Answers

Answer:

Sue is knave and Marge be knight

Step-by-step explanation:

Let Sue be knight and Marge be knave.

Sue says: "Marge is a knave". Since Sue is knight, she is right and Marge should lie.

Marge says: "Sue and I are not the same." - this is right answer too, so  this is not a correct response and our assumption is wrong.

Now, let Sue be knave and Marge be knight. Then Marge's response is right and Sue's is wrong. This is a match and this assumption is correct.

when graphed on a coordinate plane,Bumby Avenue can be represented by the equation y=-4x-7. primrose can be represented by the equation 8x+2y=17. Are these streets parallel ?

Answers

Answer:

The lines are not parallel because their slopes are opposite reciprocals.

Explanation:

The lines:

[tex]\begin{gathered} y=-4x-7 \\ \text{and} \\ 8x+2y=17 \end{gathered}[/tex]

are not parallel because their slopes are not the same

Note:

Two straight lines are said to be parallel when their slopes are the same, and have different y-intercepts.

this lettuce i have is 25 calories per serving. serving size is 85 grams. i had 27 grams. how many calories would that be??

Answers

Answer:

7.94117647059 Calories

Step-by-step explanation:

25 Calories = 85 Grams

25/85 = 0.294117647059

0.294117647059 = 1 Gram

0.294117647059 times 27 = 7.94117647059

The padlock for your gym locker uses a 3 number sequence to open the lock. If the numbers go from 1 to 27, how many different sequences are there on the dial without repeating a number?A. 17,550B. 33,696C. 16,848D. 8,775

Answers

SOLUTION:

We want to the different sequences possible without repeating a number.

For the first number, there are 27 ways to select it.

Since we aren't allowed to repeat numbers;

There are 26 ways to select the second number.

There are also 25 ways to select the third number.

Therefore, the different sequences possible are;

[tex]No\text{. of ways =}27\times26\times25=17550\text{ ways}[/tex]

Use the times and corresponding closing prices of the stock to create coordinate pairs. Let X represent the number of weeks since the first at a point, and Y represent the closing price of each time. So, X equals zero represents the data point from five years ago. There are 52 weeks in a year, and you can write the time for each closing price recorded in terms of weeks that have passed since five years ago, when X equals zero. Fill in the table to represent your data as coordinate pairs

Answers

Combining both tables we get:

NEED ASAP ILL GIVE BRAINLIEST IF CORRECT

Answers

it’s the first option .

answer: 8 square root(y^5)
because your base in the fraction is y and so you can subtract the exponents.

numerator exponent - denominator exponent so it’s:

7/8 - 1/4 that gives you 5/8 and so it’s
y^(5/8) and if you write that in the radical form it’s numerator as exponent and denominator as your radical base. therefore the final answer would be:

8 square root(y^5) . so your first option at the top

a^2 - b^4 Evaluate is a= -5 and b= 2

Answers

Answer

21

Explanations:

Given the expression

[tex]a^2-b^4[/tex]

We are to find the resulting value given that a = -5 and b = 2

[tex]\begin{gathered} =(-5)^2-(2)^2 \\ =25-4 \\ =21 \end{gathered}[/tex]

Hence the value of the expression if a = -5 and b = 2 is 21

Your brother is buying textbooks for college. He has to buy 3 math textbooks and 2 science textbooks. The total cost of his textbooks is $487. Write a linear equation to represent the cost of his textbooks.

Answers

Let's define the following variables,

x: cost of a math textbook

y: cost of a science textbook

He has to buy 3 math textbooks and 2 science textbooks, that is,

Total cost = 3x + 2y

The total cost of his textbooks is $487, then the linear equation is,

487 = 3x + 2y

Section 5.2-10. Solve the following system of equations by substitution or elimination. Enter your answer as (x,y).-2x+3y = 15-x-3y = 12

Answers

[tex]-2x+3y=15\ldots\ldots1)[/tex][tex]-x-3y=12\ldots\ldots\ldots\ldots\text{2)}[/tex]

1)-2x2)

[tex]-2x+3y-(-2x-6y)=15-2\times12\Rightarrow-2x+3y+2x+6y=15-24\Rightarrow9y=-9\Rightarrow y=-1[/tex]

y=-1 implies

[tex]-2x+3\times(-1)=15\Rightarrow-2x-3=15\Rightarrow-2x=18\Rightarrow x=-9[/tex]

Hence the solution is

[tex](-9,-1)[/tex]

-2(6.× -8 - 8 × 4)^0

Answers

[tex]-2\cdot(6\cdot(-8)-8\cdot4)^0[/tex]

Every number raised to the power of zero is equal to one.

[tex]-2\cdot1=-2[/tex]

The final expression is -2

The order in which you write the ratio is ____ to the meaning.

Answers

The ratio is defined as fraction in which one number is numertor and other number is denominator.

For example the ratio 2/3 has 2 in numerator and 3 in denominator, but if we write the ratio as 3/2 then it is different from previous ratio 2/3. So in ratio order is important in which you write the ratio.

Thus answer is,

The order in which you write the ratio is important to the meaning.

Solve the following/3x=7-3/x

Answers

Value of x is 8.46 for equation 3x=7-3/x

What is Equation?

Two or more expressions with an Equal sign is called as Equation

The given equation is 3x=7-3/x

3x+3/x=7

3x²+3=7x

3x²-7x+3=0

Use quadratic equation formula

a=3, b=-7, c=3

x=-b±√b²-4ac/2a

x=7±√49-4(3)(3)/2(3)

x=7±√49-36/6

x=7±√13/6

x=7±√2.16

x=7+1.46

x=8.46

Hence value of x is 8.46 for equation 3x=7-3/x

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For the following set of data, find the number of data within 2 population standard deviations of the mean.28, 65, 114, 74, 68, 75, 70, 69, 64

Answers

To determine the data that is within 2 population standard deviations of the mean, let's calculate the mean first.

To determine the mean, let's add all the data and divide the result by the total number of data.

[tex]28+65+114+74+68+75+70+69+64=627[/tex][tex]627\div9=69.66667[/tex]

The mean is 69.66667.

Let's now calculate the standard deviation. Here are the steps:

1. Subtract the mean from each data, then square the result.

[tex]\begin{gathered} 28-69.66667=(-41.66667)^2=1,736.1114 \\ 65-69.66667=(-4.66667)^2=21.7778 \end{gathered}[/tex][tex]\begin{gathered} 114-69.66667=(44.33333)^2=1,965.4441 \\ 74-69.66667=(4.33333)^2=18.7777 \end{gathered}[/tex][tex]\begin{gathered} 68-69.66667=(-1.66667)^2=2.7778 \\ 75-69.66667=(5.33333)^2=28.4444 \end{gathered}[/tex][tex]\begin{gathered} 70-69.66667=(0.33333)^2=0.1111 \\ 69-69.66667=(-0.66667)^2=0.4444 \\ 64-69.66667=(-5.66667)^2=32.1111 \end{gathered}[/tex]

2. Add the results in step 1.

[tex]1,736.1114+21.7778+1,965.4441+18.7777+2.7778=3,744.8888[/tex][tex]28.4444+0.1111+0.4444+32.1111=61.111[/tex][tex]3,744.8888+61.111=3,805.9998[/tex]

The sum is 3, 805.9998.

3. Divide the sum by the total number of data.

[tex]3,805.9998\div9=422.8889[/tex]

4. Square root the result in step 3.

[tex]\sqrt{422.8889}\approx20.56[/tex]

The standard deviation is approximately 20.56.

So, the data that are within 2 population standard deviations of the mean are between:

[tex]\begin{gathered} 69.67-(2)(20.56)=28.55\approx29 \\ 69.67+(2)(20.56)=110.79\approx111 \end{gathered}[/tex]

The data that are within 2 population standard deviations of the mean are between 29 and 111. Based on the given data, the data that are between 29 and 111 are the following: 64, 65, 68, 69, 70, 74, and 75. There are 7 data that are within 2 population standard deviations of the mean.

Melissa wants to rent a boat and spend at most $38. The boat costs $6 per hour, and Melissa has a discount coupon for $4 off. What are the possible numbers of hours Melissa could rent the boat?Use t for the number of hours.Write your answer as an inequality solved for t.

Answers

ANSWER:

[tex]t\leq7[/tex]

EXPLANATION:

Given:

Melissa wants to rent a boat and spend at most $38

Cost of boat per hour = $6

Discount coupon off = $4

Let t represent the number of hours

We can go ahead and set up the below inequality;

[tex]6t-4\leq38[/tex]

Let's add 4 to both sides of the inequality;

[tex]\begin{gathered} 6t-4+4\leq38+4 \\ 6t\leq42 \end{gathered}[/tex]

Let's divide both sides by 6;

[tex]\begin{gathered} \frac{6t}{6}\leq\frac{42}{6} \\ t\leq6 \end{gathered}[/tex]

So Melissa can rent the boat for up to 7 hours

How many modes does the following dataset have? 9,29,13,4,2,16,10,14,27

Answers

Given:

[tex]9,29,13,4,2,16,10,14,27[/tex]

To find- the mode of the given dataset.

Explanation-

We know that the mode is the most occuring frequency of the dataset. Let us arrange the data in ascending order first, and we get

[tex]2,4,9,10,13,14,16,27,29[/tex]

Since there is no repeated frequency, we can say that there is no mode for the given data set.

The answer is 0.

Find the distance between:(4,-9) and(-8,0)Round your answer to the nearest hundredth.

Answers

The distance between 2 points (x1, y1) and (x2, y2) is calculated as:

[tex]\text{distance}=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}[/tex]

So, if we replace (x1, y1) by (4, -9) and (x2, y2) by (-8,0), we get:

[tex]\begin{gathered} \text{distance}=\sqrt{(-8-4)^2+(0-(-9))^2} \\ \text{distance}=\sqrt{(-12)^2+(9)^2} \\ \text{distance}=\sqrt{144+81} \\ \text{distance}=\sqrt{225} \\ \text{distance}=15 \end{gathered}[/tex]

Answer: the distance is 15

For an arc length s, area of sector A, and central angle θ of a circle of radius r, find the indicated quantity for the given value. r= 6.45 in, θ= 5 pi\6, s=?

Answers

Calculate the arc length by using the following formula:

[tex]s=r\theta[/tex]

Replace the values of r and θ and simplify:

[tex]\begin{gathered} s=(6.45in)(5\frac{\pi}{6})=(6.45)(\frac{5}{6})(3.14) \\ s=16.8775in \end{gathered}[/tex]

Hence, the arc length is 16.8775 in

A loaded S-sided de is loaded so that the number 4 occurs 3/10 of the time while the other numbers occur with equal frequency. What is the expected value of this die? CASS 08.44 OC.48 Next O My

Answers

The probablity of obtain a 4 is= 3/10

The probablity of obtain a 1,2,3,5,6,7,8= 1-3/10=7/10

The expect value is:

[tex]E(p)=X1*p1+X2*p2+X3*p3+...+X8*p8[/tex]

And p(1)=p(2)=p(3)=p(5)=p(6)=7/10

All have the same frequency, therefore

p(1,2,3,5,6,7,8)=7/10*1/5=7/50=1/10

Where x=1, 2 ,3,4,5,6 and p=3/10 if is 4 and 7/10 for any other number.

Replacing:

[tex]\begin{gathered} E=(1+2+3+5+6)*\frac{7}{50}+4*\frac{3}{10} \\ \\ E=2.38+1.2=3.58\approx4 \end{gathered}[/tex]

2.) Part A: complete the following table for the functions

Answers

Complete the following table for the functions:

[tex]\begin{gathered} f(x)=x^2+1 \\ g(x)=f(x-5) \\ h(x)=f(x+3) \end{gathered}[/tex]

The below function represents the transformation of the independent variables:

[tex]\begin{gathered} f(x)=x^2+1 \\ g(x)=f(x-5)\ldots\ldots\text{.f(x) will decrease by 5 units} \\ h(x)=f(x+3)\ldots\ldots.f(x)\text{ will increase by 3 units} \end{gathered}[/tex]

CASSANDRA WENT FOR A JO9.SHE RAN AT A PACE OF 7.3 MILESPER HOUR. IF SHE RAN FOR 0.75HOURS, HOW FAR DID CASSANDRARUN?

Answers

We can use one simple formula, that is d=vt

d=distance

v=pace

t=time

So,

d=(7.3miles per hour)(0.75 hours)=5.475 miles

Good evening, I need help on this questions. Thanks :)

Answers

Answer:

A and B ---> decreasing

B and C ---> constant

C and D ---> decreasing

D and E ---> increasing

Explanation:

A function is increasing if we go from left to right and the graph goes up, it is constant when it is a horizontal line and it is decreasing if when we go from left to right the graph goes down.

Therefore, for each part of the function, we get

A and B ---> decreasing

B and C ---> constant

C and D ---> decreasing

D and E ---> increasing

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The general form of an ellipse is 15x2+4y2+30x−16y−29=0.

What is the standard form of the ellipse?

Answers

The equation of ellipse in standard form is (x + 1)² / 4 + (y - 2)² / 15 = 1.

How to determine the standard form of the ellipse

In this problem we find the equation of an ellipse in general form, whose standard form can be found by algebra properties. The general form of the equation of an ellipse centered at (h, k) is introduced below:

(x - h)² / a² + (y - k)² / b² = 1

Where:

a, b - Lengths of the semiaxes.(h, k) - Coordinates of the center.

The complete procedure is now presented:

15 · x² + 4 · y² + 30 · x - 16 · y - 29 = 0

(15 · x² + 30 · x) + (4 · y² - 16 · y) = 29

15 · (x² + 2 · x) + 4 · (y² - 4 · y) = 29

15 · (x² + 2 · x + 1) + 4 · (y² - 4 · y + 4) = 29 + 15 · 1 + 4 · 4

15 · (x + 1)² + 4 · (y - 2)² = 29 + 15 + 16

15 · (x + 1)² + 4 · (y - 2)² = 60

(x + 1)² / 4 + (y - 2)² / 15 = 1

The equation of ellipse is (x + 1)² / 4 + (y - 2)² / 15 = 1.

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find two vectors each of norm 1 that I perpendicular to vector A={3,2}​

Answers

(2√13/13 , 3√13/13) and  (-2√13/13 , -3√13/13) are two vectors of norm 1  that are perpendicular to A = (3 , 2) .

What is perpendicular vectors ?In Cartesian coordinates, the given vector can be represented by the line y = -2x/3. The vector is the line segment that connects (0,0) and (3,-2).

             y = 3x/2 can be used to represent the normal.

If the vector is represented by a line connecting (0,0) to a point (p,q), then,

              p2 + q2 = 1 because the normal is one length, and q = 3p/2.

As a result,

             p² + 9p²/4 = 1, 13p²/4 = 1, p = ±√(4/13) = ±2/√13, q = ±3/√13.

After rationalization, one normal vector is (2√13/13 , 3√13/13) and the other is (-2√13/13 , -3√13/13).

The two vectors of norm 1 perpendicular to A = (3 , 2) is :

(2√13/13 , 3√13/13) and  (-2√13/13 , -3√13/13).

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QUESTION 31 POINTThe area of a triangle is 18. The base is 6 inches. What is the height? Do not include units in your answer.

Answers

ANSWER:

6

STEP-BY-STEP EXPLANATION:

The area of a triangle is given by the following equation:

[tex]A=\frac{b\cdot h}{2}[/tex]

We replace and solve for h (height)

[tex]\begin{gathered} 18=\frac{6\cdot h}{2} \\ h=\frac{18\cdot2}{6} \\ h=6 \end{gathered}[/tex]

The height of the triangle is 6 inches

hi, can you help me answer this question please, thank you!

Answers

Answer:

The correct option is B

Explanation:

The given statement shows that there is a 95% chance that the mean of a sample of 29 gadgets will be between 12.8 and 34.9

Jodie is an event planner who believeseach person requires 3.75 feet ofpersonal space at her events. Her nextevent will be at a venue that measures40 feet by 75 feet. How many peopleshould she include on the guest list?

Answers

The venue measures 40 ft by 75 ft . This means the venue has the shape of a rectangle. A rectangle

what is the solution set for the inequality
A. x ≤ -5
B. x ≤ 5
C. x ≤ 1
d. x ≤ -14

Answers

The solution set to the inequality, 4x + 12 ≤ -8, is determined as: A. x ≤ -5.

How to Find the Solution Set of an Inequality?

The solution set is the value of x that would make an inequality statement true. To find the value of x, solve as you would solve a normal equation.

Using the key to the given model in the diagram, we can write the inequality as follows:

On the left, we would have, 4x + 12.

On the right, we would have, -8.

The inequality would be expressed as:

4x + 12 ≤ -8

Solve for x

4x + 12 - 12 ≤ -8 - 12 [subtraction property of equality]

4x ≤ -20

4x/4 ≤ -20/4

x ≤ -5

The solution set is: A. x ≤ -5.

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Debra will rent a car for the weekend. She can choose one of two plans. The first plan has an initial fee of $50 and costs anadditional $0.15 per mile driven. The second plan has an initial fee of $59 and costs an additional $0.11 per mile driven.for what amount of driving do the two plans cost the same? i need the answer for miles and cost

Answers

First plan cost is modeled as:

50 + 0.15x

where x are the miles driven

Second plan cost is modeled as:

59 + 0.11x

If the two plans cost the same, then:

50 + 0.15x = 59 + 0.11x

0.15x - 0.11x = 59 - 50

0.04x = 9

x = 9/0.04

x = 225 miles

which corresponds to a cost of:

50 + 0.15*225 = $83.75

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