A curious patterns occurs in a group of people who all shake hands with one another. It turns out that you can predict the number of handshakes that will occur if you know the number of people. If we are in a room of 5 people, we can determine the number of handshakes by this line of reasoning: The first person will shake 4 hands (she won’t shake her own). The second person will shake 3 hands (he won’t shake his own of the hand of the first person, they already shook). The third person will shake 2 hands (same reasoning). The fourth person will shake 1 hand (that of the fifth person). The fifth person will shake 0 hands. So there will be a total of 1+2+3+4=10 handshakes

Answers

Answer 1

Missing part of the question

Determine the number of handshakes, i, that will occur for each number of people, n, in a particular room. (people)

Answer:

[tex]S_n = \frac{n}{2}(n - 1)[/tex]

Step-by-step explanation:

Given

For 5 people

[tex]\begin{array}{cc}{People} & {Handshakes} & {5} & {4} & {4} & {3} & {3} & {2} & {2} & {1} & {1} & {0} &{Total} & {10} \ \end{array}[/tex]

Using the given instance of 5 people, the number of handshakes can be represented as:

[tex](n - 1) + (n - 2) + (n - 3) + ........ + 3 + 2 + 1 + 0[/tex]

The above sequence is an arithmetic sequence and the total number of handshakes is the sum of n terms of the sequence.

[tex]S_n = \frac{n}{2}{(T_1 + T_n})[/tex]

Where

[tex]T_1 = n - 1[/tex] --- The first term

[tex]T_n = 0[/tex] --- The last term

So:

[tex]S_n = \frac{n}{2}(n - 1 + 0)[/tex]

[tex]S_n = \frac{n}{2}(n - 1)[/tex]


Related Questions

Can somebody help me. Will Mark brainliest.

Answers

Answer:

both are true

Step-by-step explanation:

have a great day

it would be true for both

3x
The first and second steps to solve the equation
+5= 20
are shown below.

+5-5= 20-5
3x ( 5
5 3
= 15
5
3
Which property was applied in the second step?
ОО ОО
Addition Property of Equality
Subtraction Property of Equality
Multiplication Property of Equality
Division Property of Equality

Answers

Answer:

Multiplication property of equality

Step-by-step explanation:

I'm sorry if its wrong

could you mark me brainliest pls

Have a good one

Kevin is doing an experiment where he flips a fair coin 20 times and analyzes the results. The coin has come up heads the first 19 trials. What is the conditional probability that the next flip will come up tails, given that the previous 19 flips were heads? Explain why your answer makes sense.

Answers

Answer:

it's still 50%

each flip is an independent probability. what happened the first 19 times is irrelevant, because it's still a 50-50 chance on any independent flip.


A recipe called for the ratio of sugar to flour to be 10: 1. If you used 90 ounce of sugar, how
many ounces of flour would you need to use?

Answers

Answer:9 ounces of flours

Step-by-step explanation:90:9 ratio or sugar to flour

In the figure below, m 2 2 = 76°. Find m Z1, m3, and m 24.
m 21 =
= 0
4
1
m 23 =
3
2.
m 24

Answers

Answer:

Chapter 2 Review WS. Period: Date: 1. A transversal intersects two parallel lines. ... 2. Find the measure of angles 1-4 and 6-8, using the following diagram. meisen ... 4. Find the measure of angles 1-7 given that lines m and n are parallel and t is transversal. ... Find the measure of angle 1. m24 = 123, mZ1 = 2x, mZ2 = x +42.

Step-by-step explanation:

A rectangular garden measuring 28 m by 45 m is bordered (and surrounded) by a fence. Inside, a walk that is 4 m wide goes all the way along the fence. Find the area of this walk. Be sure to include the correct unit in your answer.

Answers

Answer:

1219 square feet

Step-by-step explanation:

cause

can some on plz help me with this!!
y=6x-11
-2x-3y=-7
find the solution plz

Answers

if you solve using subsitution, the point form would be (2,1) and the equation form = 2, y=1

Answer:

x = -2

y = -23

(x, y) --> ( -2, -23)

Step-by-step explanation:

y = 6x - 11

-2x - 3y = -7

***What you need to do is substitute the "y" with what has been given to us which is "6x - 11"***

-2x - 3(6x - 11) = -7

Now what you need to do, is use the distributive property (multiply what is in the parenthesis "6x - 11" by what is outside of it "3").

-3 × 6x and -3 × -11

-18x and 33

Now we have......

-2x - 18x + 33 = -7

Now we can combine like terms (put the numbers that are the same together - variables with variables, and whole numbers with whole numbers)

-2x - 18x = -20x (2 negatives added together gives u a result of a bigger negative number)

-20x + 33 = -7

Now we need to subtract 33 on both sides

-20x + 33 - 33 = -7 - 33

-20x = -40

Now we need to divide by -20 on both sides to isolate the variable

-20x ÷ -20 = -40 ÷ 20

x = -2

Now that we have what "x" is, we can use that to find what "y" is....

y = 6x - 11

Substitute the "x" with the answer we got "-2".

y = 6(-2) - 11

y = -12 - 11

y = -23

x = -2

y = -23

Now we can check our work

y = 6x - 11

All we need to do is substitute the "x" and "y" with the answer we got above.

y = 6x - 11

-23 = 6(-2) - 11

-23 = -12 - 11

-23 = -23

CORRECT

So now that we checked our work, and saw that it was correct, I can hereby say that x is -2 and y is -23

x = -2

y = -23

(x, y) --> ( -2, -23)

Hope this helped!!!

I need help on this pls help meh

Answers

Answer:

the missing side T-F is 8. the missing side F-K is 3.

Step-by-step explanation:

hope I helped

Answer:

(SR*ST)+(FK*KL)=66cm²

Step-by-step explanation:

RL=ST+F K

9= 6+x

F K=3

T F=8

Area of this figure= (3*2)+(6*10)

=6+60=66 cm²

Rafael got 3 boxed candies and 1 bag of chips for $6.99. His sister got 2 bags of chips and 1 boxed candy for $5.98. Find the cost for 1 of each of these items in dollars.

Answers

Answer:

Step-by-step explanation:

Let us represent

Boxed candles = x

Bag of chips = y

Rafael got 3 boxed candies and 1 bag of chips for $6.99.

3x + y = 6.99....Equation1

His sister got 2 bags of chips and 1 boxed candy for $5.98.

x + 2y = 5.98......Equation 2

Find the cost for 1 of each of these items in dollars.

Write the word sentence as an equation and then solve
-7 increased by a number n is 12

A: -n - 7 = 12n = -19
B: 12+n = -7n = 7/12
C: -7 + n =12n=19
D: None of the Above

Answers

Answer:

It may be C or D

I think its C.

Sorry if I'm wrong.

Step-by-step explanation:

Answer:

C

Step-by-step explanation:

let the number be n then increasing - 7 by n is - 7 + n and

- 7 + n = 12 ( add 7 to both sides )

n = 19

in a Recipe, 125 ml of milk is used for every half litre of water what is the ratio of milk to water​

Answers

Answer:

1 : 4

Step-by-step explanation:

half litre = 500 ml

Milk : water = 125 : 500

                   = 125 ÷ 25  : 500÷25

                   = 5 : 20

                    = 1 : 4

I suck at shapes so uh thanks

Answers

The answer would be 16=3x
16=3x is your answer

Given the system of equations:
2x + 2y = 12
X-y= 2
What is x equal to?

8
4
2
1
-2​

Answers

Answer:

x=4

y=2

Step-by-step explanation:

2x+2y=12

x−y=2

​In order to solve by elimination, coefficients of one of the variables must be the same in both equations so that the variable will cancel out when one equation is subtracted from the other.

2x+2y=12,x−y=2

To make 2x and x equal, multiply all terms on each side of the first equation by 1 and all terms on each side of the second by 2.

2x+2y=12,2x+2(−1)y=2×2

Simplify.

2x+2y=12,2x−2y=4

Subtract 2x−2y=4 from 2x+2y=12 by subtracting like terms on each side of the equal sign.

2x−2x+2y+2y=12−4

Add 2x to −2x. Terms 2x and −2x cancel out, leaving an equation with only one variable that can be solved.

2y+2y=12−4

Add 2y to 2y.

4y=12−4

Add 12 to −4.

4y=8

Divide both sides by 4.

y=2

Substitute 2 for y in x−y=2. Because the resulting equation contains only one variable, you can solve for x directly.

x−2=2

Add 2 to both sides of the equation.

x=4

The system is now solved.

x=4,y=2

Correct choice is B) x=4.

answer is 4

because y=2 then you subsistute it in and then you find X

x-y=2 turns to x=y+2 then you subsistute that into x of the equation 2x+2y=12 which then is 2(y+2)+2y =12 and you should get y=2 then you grab the other equation x-2=2 and you should get x=4

ORDER
ORDER OF OPERATIONS
21 divided by 3 +4

Answers

Answer:

11

Step-by-step explanation:

21/3+4

7+4

11

.......

What single percentage change is equivalent to a 11% increase followed by a 13% increase?

Answers

Answer:

The equivalent percentage change is [tex]25.43[/tex] %

Step-by-step explanation:

Let there be a number 100

It is first increased 11 % , so the new number would be [tex]100 + 11[/tex]% of 100

i.e [tex]100 + 11 = 111[/tex]

Now, this number 111 is further increased by 13 % so the new number is [tex]111 + 13[/tex]% of 111

125.43

So , the total increase or equivalent increase is

[tex]\frac{125.43-100}{100} *100\\= 25.43[/tex]%

PLS HELP ME FAST FREE 16 POINTS Rectangle PQRS is graphed on a coordinate plane with vertices P(–2, 1), Q(–2, 4), R(–4, 4), and S(–4, 1), as shown below.
Rectangle PQRS is reflected over the y–axis and then translated 2 units to the left. What are the coordinates of P'?
O(1, 0)
O(0, 1)
O(4, 1)
O(–4, –1)

Answers

Answer:

Pretty sure it's B!

Step-by-step explanation:

Over the Y axis- (2,1)

To the left two times= (0,1)

Hope this helped!

Answer:

(0,1)

Step-by-step explanation:

Since the problem is only asking about P', let's ignore the rest of the rectangle. P's coordinates are to be reflected across the y-axis, putting P' at (2,1). Move P' left by two units and your 'x' is 0, your 'y' is the same. So, (0,1)

ABC is an isosceles triangle. Z A is the vertex angle, AB = 4x – 14 and AC = x + 10. Find the length of one of the legs. The length of one of the legs is ...

Answers

Answer:

18 units

Step-by-step explanation:

A picture of what it would look like is at the bottom.

You know that the legs are equal because it's isosceles, so AB = AC. This means:

[tex]4x - 14 = x + 10\\3x - 14 = 10\\3x = 24\\x = 8[/tex]

using the rules of solving an equation.

The length of one leg is:

[tex]x + 10\\8 + 10\\18[/tex]

PLS HELP GUYS I WILL DO ANYTHING

Answers

Answer:

X=6

Step-by-step explanation:

THE answer IS :X=6

HOPE IT HELPED

What is the measure of RST?


What is the measure of angle VWT?

What’s the measure of angle STR?


will give b if correct! HELPPP I HAVE A TEST TOMORROW:(

Answers

Answer:

Step-by-step explanation:

Measure of RST-- 79*

Measure of angle VWT-- 33*

Measure of angle STR--  68*

Write an expression for y more than 2

Answers

Answer:

2 + y

Step-by-step explanation:

all you must do is add y to 2

1/6 + -2/3 = ?

I’ll give best review

Answers

1/6 + -2/3=
1/6- 2/3 | get 2/3 to be over 6 (3 goes into 6 twice so we multiply 2 by 2)
1/6- 4/6
=-3/6
=-1/2

Find the surface
area of 11mm 8mm 22mm

Answers

Answer: The chosen topic is not meant for use with this type of problem. Try the examples below.

Step-by-step explanation:

PLEASE HELP URGENT!!!! What is the y intercept? the graph is in the problem and the slope is 90

Answers

Answer:

y-intercept is 30

Step-by-step explanation:

(101)² solve it using identities​

Answers

Answer:

10201

Step-by-step explanation:

=(101)²

=(100+1)²

={100²+2(100)(1)+1²} [(a+b)²=a²+2ab+b²]

=10000+200+1

=10201

Solution :-

Given,

(101)^2

We need to solve it using identities.

>> (100 + 1)^2

As we know that,

>> (a + b)^2 = a^2 + b^2 + 2ab

Here,

a = 100 b = 1

Using the identity we gets,

>> (100)^2 + (1)^2 + 2(100)*(1)

>> 10000 + 1 + 200

>> 10000 + 201

>> 10201

triangle ABC is similar to triangle EHG , find the measure of angle EHG .

Answers

Answer:

[tex]\angle EHG = 80[/tex]

Step-by-step explanation:

Given

ABC ∼ EHG

See attachment

Required

Determine [tex]\angle EHG[/tex]

First, we calculate x in ABC

[tex]x + 2x + 60= 180[/tex]

[tex]3x + 60= 180[/tex]

[tex]3x = 120[/tex]

[tex]x = 40[/tex]

The corresponding angle to [tex]\angle EHG[/tex] is [tex]\angle ABC[/tex]

and

[tex]\angle ABC = 2x[/tex]

[tex]\angle ABC = 2 * 40[/tex]

[tex]\angle ABC = 80[/tex]

Hence:

[tex]\angle EHG = 80[/tex]

Help please I will give you the brainliest

Answers

Answer:

Step-by-step explanation:

The answer is 570 because if you multiply 38 times 15 = 570 so it is 570. Thank you for answering to hope this helps you if you need more help contact me!

Answer:

$5.70

Step-by-step explanation:

Since it is 15% to make it a decimal you would move the decimal 2 places to the left to make it 0.15 and then multiply like this 38(.15) which is 5.7. So, shipping and handling is $5.70.

slove this and get brainliest!!
please be sure of your answer!!!!!!!​

Answers

Answer:

Option A

37°

Step-by-step explanation:

4x+ 2 = 150° [Vertically Opposite Angles]

=> 4x = 150 - 2

=> 4x = 148

[tex] = > x = \frac{148}{4} [/tex]

=> x = 37° (Ans)

Answer:

(4x+2)°=150°[by vertical opposite angles]

4x=150-2

4x=148

x=148/4

x=37

Which of the following is an example of categorical data?

a
total value of pennies stored in a jar
b
temperature reading on a thermometer
c
type of music most listened to on the radio
d
number of steps it takes to walk around a building

Answers

Answer:

type of music listened to on the radio

I’d appreciate if someone could help me out lol

Answers

Answer:

a) OP:RT = 10:3

b) OQ = 15 cm

c) m<P = [tex]60^{o}[/tex]

d) m<Q = [tex]94^{o}[/tex]

Step-by-step explanation:

Given that: ΔOPQ is similar to ΔRTS

Then;

a) OP:RT = 12:3.6

                 = [tex]\frac{120}{36}[/tex]

                = [tex]\frac{10}{3}[/tex]

                = 10:3

The ratio of OP to RT is 10:3.

b) The measure of length OQ = [tex]\frac{10}{3}[/tex] x 4.5

                                 = 15 cm

c) m<P ≅ m<T

So that,

m<P = [tex]60^{o}[/tex]

d) m<Q ≅ m<S

But,

26 + 60 + m<S = 180 (sum of angles in a triangle)

86 + m<S = 180

m<S = 180 - (86)

        = [tex]94^{o}[/tex]

Thus,

m<Q = [tex]94^{o}[/tex]

what is 8% of 83. Thank you guy's for all of the help.

Answers

Answer:

6.64 :)

Step-by-step explanation:

83/x = 100%/8%/

Reciprocal is x/83 = 8/100. Cross multiply we get 6.64 :)!

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