What is the sum of n natural numbers: 1+2+...+n?

Answers

Answer 1

Answer:

S = 1/2 n (n+1)

Step-by-step explanation:

1 + 2 + 3 + ... + n

Now write in reverse order:

n + n-1 + n-2 + ... + 1

Add together:

n+1 + n+1 + n+1 + ... + n+1

n (n+1)

Since this is double the sum:

S = 1/2 n (n+1)

Answer 2

Answer:

1/2n(n+1)

Step-by-step explanation:


Related Questions

I don’t understand it

Answers

So first you have to find the volume of the entire tank using the height of 6cm. Then you have to find the volume of just the water using the height of 4 cm. Then you subtract both of your volumes and that will represent the volume of the part of the tank that isn't filled with water

Answer:

432cm³

Step-by-step explanation:

First we need to find the volume.

Use the volume formula.

[tex]V=l*w*h[/tex]

Plug in the values.

[tex]V=18*12*6\\ \\ V=1296[/tex]

Now find the volume of water we filled up.

[tex]V=18*12*4\\ \\ \\V=864[/tex]

Now we can subtract to find how much more water we need.

[tex]V=1296-864\\ \\ \\V=432[/tex]

432cm³ of water is needed to fill up the tank completely.

PLEASE HELP!!!!

Mike says that if he doubles each dimension of any rectangular prism, the surface area also doubles. Is Mike correct? Give an example to support your answer.

Answers

Answer:

Mike is not right

Step-by-step explanation:

we know that

If two figures are similar, then the ratio of its surface areas is equal to the scale factor squared

Let

z----> the scale factor

x----> surface area of the enlarged rectangular prism

y-----> surface area of the original rectangular prism

[tex]z^{2}=\frac{x}{y}[/tex]

so

In this problem we have

[tex]z=2[/tex]

substitute

[tex]2^{2}=\frac{x}{y}[/tex]

[tex]4=\frac{x}{y}[/tex]

[tex]x=4y[/tex]

so

The surface area of the enlarged rectangular prism is 4 times the surface area of the original rectangular prism

therefore

Mike is not right

Verify with an example

we have a rectangular prism

[tex]L=5\ m[/tex]

[tex]W=2\ m[/tex]

[tex]H=3\ m[/tex]

The surface area of the prism is equal to

[tex]SA=2(LW)+(2L+2W)H[/tex]

substitute the values

[tex]SA=2*(5*2)+(2*5+2*2)*3=62\ m^{2}[/tex]

If he doubles each dimension of any rectangular prism

then

the new dimensions will be

[tex]L=5*2=10\ m[/tex]

[tex]W=2*2=4\ m[/tex]

[tex]H=3*2=6\ m[/tex]

The new surface area will be

[tex]SA=2*(10*4)+(2*10+2*4)*6=248\ m^{2}[/tex]

[tex]248/62=4[/tex]

therefore

The surface area of the enlarged rectangular prism is 4 times the surface area of the original rectangular prism

Find the value of x.

Answers

Answer:

x=60

Step-by-step explanation:

As the sides of the triangle are doubled (21 to 42 and 44 to 88) that means that the side of 30 is doubled to 60

Answer:

x=60

Step-by-step explanation:

find the slope of the line that passes through -2 -2 and 2 -4

Answers

Answer:

-1/2

Step-by-step explanation:

To find the slope we know that:

Slope = (Y2-Y1)/(X2-X1)

Then, given the two points, we have that:

(X1, Y1) = (-2,-2)

(X2, Y2) = (2, -4)

Then:

m= (Y2-Y1)/(X2-X1) = (-4-(-2))/(2-(-2)) = -4+2/2+2 = -2/4 = -1/2

So the slope of the function that passes through those points is: -1/2

A local clothing shop is marking down all of its summer clothes by 75%. sarah would like to purchase a swimsuit that is originally priced at $80. when she gets to the register, she signs up for a loyalty cars that saves her an additional 10%. how much did she spend on the swimsuit and what total percent did she receive off?


a. Find the markdown price of the swimsuit.

b. Then, find the markdown of the loyalty card.

c. Subtract to find the final price.

Answers

Answer:

$18.00

Step-by-step explanation:

75% of 80$ is 60$ .    

80$-60$=20$

10%of20$=2$

20$-2$=18$

18$

She spend $18 on the swimsuit and she gets total 77.5 percent off.

Given local clothing shop is marking down all of its summer clothes by 75%.

And Sarah would like to purchase a swimsuit that is originally priced at $80.

So, the markdown price of swimsuit will be ( $80 - 75 % of $80).

Now 75% of $80 is equals to $60.

So the markdown price of swimsuit will be ($80 - $60) or $20.

Again, when she gets to the register, she signs up for a loyalty cars that saves her an additional 10%.

So 2% of $20 dollar will be $2.

Now the final markdown price of swimsuit will be ($20-$2) or $18 .

Total discount she get is of ($80 - $18) or $62.

The percent amount she gets off = [tex]\frac{62}{80} \times100%[/tex] %.

=[tex]0.775 \times100[/tex]%.

[tex]=77.5[/tex]%.

She spend $18 on the swimsuit and she gets total 77.5 percent off.

For more details on percentage follow the link:

https://brainly.com/question/16797504

Solve -2(2x+5) -3(x-1)

Answers

Hello!

The answer is:

[tex]-2(2x+5)-3(x-1)=-7x-7\\[/tex]

Why?

To solve the problem, we need to perform the operations and then, add like terms.

We need to apply the distributive property, which is defined by the following way:

[tex]a(b+c)=ab+ac[/tex]

Also, we need to remember how to add like terms. Like terms are terms that share the same exponent and the same variable, for example:

[tex]3x+5x+x^{2}=8x+x^{2}[/tex]

We were able to add only the first two terms since they are like terms, both are sharing the same exponent and the same variable.

So, we are given the expression:

[tex]-2(2x+5)-3(x-1)[/tex]

Then, solving we have:

[tex]-2(2x+5)-3(x-1)=-4x-10-(3x-3)\\\\-4x-10-(3x-3)=-4x-10-3x+3\\\\-4x-10-3x+3=-4x-3x-10+3\\\\-4x-3x-10+3=-7x-7[/tex]

Hence, we have that the answer is:

[tex]-2(2x+5)-3(x-1)=-7x-7\\[/tex]

Have a nice day!

-6x+5y=14
-6x+7y=-11
-6x+7y=11
-7x+6y=-11

Anything helps owo

Answers

Answer:

-6x + 7y = 11

Step-by-step explanation:

The point-slope form of an equation of a line:

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

m - slope

The formula of a slope:

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

We have the points (-3, -1) and (1/2, 2). Substitute:

[tex]m=\dfrac{2-(-1)}{\frac{1}{2}-(-3)}=\dfrac{3}{3\frac{1}{2}}=\dfrac{3}{\frac{7}{2}}=3\cdot\dfrac{2}{7}=\dfrac{6}{7}\\\\y-(-1)=\dfrac{6}{7}(x-(-3))\\\\y+1=\dfrac{6}{7}(x+3)}[/tex]

Convert to the standard form Ax + By = C:

[tex]y+1=\dfrac{6}{7}(x+3)[/tex]           multiply both sides by 7

[tex]7y+7=6(x+3)[/tex]              use the distributive property

[tex]7y+7=6x+18[/tex]                subtract 7 from both sides

[tex]7y=6x+11[/tex]             subtract 6x from both sides

[tex]-6x+7y=11[/tex]

A ball is dropped from the top of a building. the height of the ball after x bounces can be represented by the expression 40(0.75)^x.

What does the in the expression 40 represent??

Answers

Answer:

I believe 40 is the height from which the ball was dropped

In the expression \( 40(0.75)^x \), the number 40 represents the initial height from which the ball is dropped. This initial height refers to the height of the ball above the ground before it experiences any bounces.
The expression itself describes a geometric sequence where the height of the ball after each bounce is a certain fraction of the height from the previous bounce. In this particular case, after each bounce, the ball reaches a height that is 75% (or 0.75 times) of the height of the previous bounce.
To break it down further:
- \( 40 \) is the initial height (in meters, feet, or another unit of measurement) where the ball was dropped from the top of the building.
- \( 0.75 \) is the common ratio, representing the fact that the ball loses 25% of its height with each bounce. It means that the ball only reaches 75% of the height it reached after the previous bounce.
- \( x \) is the number of bounces.
So, after the first bounce (when \( x = 1 \)), the height of the ball would be \( 40 \times 0.75 \). After the second bounce (when \( x = 2 \)), the height would be \( 40 \times 0.75^2 \), and so on for each subsequent bounce, following the pattern of a geometric sequence.

At the Rolling Ridge School spelling bee, 75% of the
contestants advanced to the second round and 60% advanced
to the third round. What is the probability that a randomly
selected contestant advanced to the third round given the same
contestant advanced to the second round?
A. 3/20
B. 9/20
c. 7/15
D. 4/5

Answers

Answer: Option D

[tex]P (B | A) =\frac{4}{5}[/tex]

Step-by-step explanation:

Call A to the event in which a student advances to the second round.

We know that:

[tex]P (A) = 75\% = 0.75[/tex]

Call B the event in which a student advances to the third round.

We know that:

[tex]P (B) = 60\% = 0.6[/tex]

We then look for the probability of B given A. This is:

[tex]P (B | A) =\frac{P(B\ and\ A)}{P(A)}[/tex]

In this case, the probability of B and A is equal to the probability of B, since the students who advance to the third round also advanced to the second round before

[tex]P (B | A) =\frac{P(B)}{P(A)}[/tex]

[tex]P (B | A) =\frac{0.6}{0.75}[/tex]

[tex]P (B | A) =\frac{4}{5}[/tex]

Write the word sentence as an equation. Number c increased by 6 is the same as 23

Answers

C+6=23 just go step by step dawg

find the slope (4,4) (4,9)​

Answers

Answer:

Undefined

Step-by-step explanation:

Slope form:

m (slope) = (y₂ - y₁)/(x₂ - x₁)

Let:

(x₁ , y₁) = (4 , 4)

(x₂ , y₂) = (4 , 9)

Plug in the corresponding numbers to the corresponding variables.

m = (9 - 4)/(4 - 4)

Simplify

m = (5)/(0)

m = undefined

Undefined is your answer, for there cannot be a 5/0. You cannot have 5 parts of nothing.

~

Linda Young opened up a computer service company. To pay for start up cost Linda borrowed $79,000 from a bank at 15% for 1 year. Find the interest for the year

Answers

Interest=Principal×Rate×Time

I=PRT/100

I= 79000×15×1

100

I= 1185000

100

I= $11850

To confirm

11850/79000 ÷ 100

= 0.5 ×100

= 15% (rate)

The interest of one year is $11850.

What is simple interest?

easy interest is based on the essential amount of a loan or the primary deposit in a savings account.

calculation:-

Amount of money borrowed by Linda = $79000

rate of interest =15%

Interest amount= $79000*15/100

  The interest of the year =$11850

Learn more about simple interests here:-https://brainly.com/question/2294792

#SPJ2

Devon made a scale drawing of a triangle. He used a scale factor 1/4 to draw the new triangle. How does each side of the new triangle compare to the original?

Answers

Answer:

The sides of the new triangle compared to the original are 4 times smaller.

Step-by-step explanation:

we know that

If two figures are similar, then the ratio of its corresponding sides is proportional and this ratio is called the scale factor

Let

z-----> the scale factor

x----> the corresponding side of new triangle

y----> the corresponding side of the original triangle

[tex]z=\frac{x}{y}[/tex]

we have

[tex]z=\frac{1}{4}[/tex]

substitute

[tex]\frac{1}{4}=\frac{x}{y}[/tex]

[tex]x=\frac{1}{4}y[/tex]

therefore

The sides of the new triangle compared to the original are 4 times smaller.

Answer:

C

Step-by-step explanation:

What is the sum of 1/9, 2/3, and 5/18?

A. 4/15
B. 19/18
C. 8/30
D. 12/9

Answers

The correct answer is B.

1/9 can be converted into 2/18. 2/3 can be converted into 12/18. 2/18 + 12/18 + 5/18 = 19/18. The answer is B

Travis just started high school and he wants to manage his time wisely. He schedules 3/2 hours each day for homework, 1/2 of an hour each day for chores at home, and 17/2 hours each day for sleep. How many hours each day are scheduled for these activities?

Answers

hw: 3/2hrs = 3×30 = 90mins

chores: 1/2hr = 1×30 = 30mins

sleep: 17/2hrs = 17×30 = 510mins

90+30+510=630mins=10.5hrs/day

Answer:

21/2

Step-by-step explanation:

khan academy got right

Which of the following statements are true? Select all that apply. This is Algebra Nation

Answers

Answer:

241

Step-by-step explanation:

If you are going to use the SAS postulate to prove these two triangles congruent what additional information do you need

Answers

Answer:

Option D. ET=IT

Step-by-step explanation:

we know that

The Side Angle Side postulate (SAS) states that if two sides and the included angle of one triangle are congruent to two sides and the included angle of another triangle, then these two triangles are congruent

In this problem

the included angle ∠ETK of triangle TEK is congruent with the included angle ∠KTI of triangle TIK

the side KT is a common side both triangles

therefore

ET must be equal to IT to prove that triangles TEK and TIK are congruent by SAS postulate

See attachment below. Please answer. Thank you.

Answers

Hi

The probability of landing a green side up is 2 / 6 .

Hope this helps

Answer:

C. 2/6

Step-by-step explanation:

We know that a block has 6 sides.

There are 2 green sides.

Now all we do is put the number of green sides over the number of sides the block has.

2/6 is our answer.

The product of 43 x 6 can be broken down into expanded
form.
What is the missing expression?
43 x 6
= (40 6) + (?)
3x6
6x6
40 x 1
40 x 3

Answers

Answer:3*6

Step-by-step explanation: It is (40*6)+(3*6) you have to break it down

Sue danced for 15.5 minutes.Allie danced for 23.25 minutes. Carol danced for 8 minutes and 12 seconds less than Sue and Allie combined. How much time in minutes and seconds fed the girls dance altogether

Answers

Answer:69.38

Step-by-step explanation: Sue = 15.5 allie = 23.25 carol = 15.5+32.25 - 8.12 2.   15.5+32.25=38.75-8.12=  30.63 now all together 23.25+15.5+30.63= 69.38

The girls danced for a total of 30 minutes and 33 seconds.

First, we need to calculate the total time Sue and Allie danced combined:

Sue danced for 15.5 minutes, which can be written as [tex]\(\frac{155}{10}\)[/tex] minutes.

Allie danced for 23.25 minutes, which can be written as [tex]\(\frac{2325}{100}\)[/tex] minutes.

To combine these times, we need a common denominator, which is 100:

Sue's time in minutes: [tex]\(\frac{155 \times 10}{100} = \frac{1550}{100}\)[/tex]

Allie's time in minutes: [tex]\(\frac{2325}{100}\)[/tex]

Now we add Sue's and Allie's times:

[tex]\(\frac{1550}{100} + \frac{2325}{100} = \frac{3875}{100}\)[/tex]

Converting this back to mixed numbers:

[tex]\(\frac{3875}{100} = 38\)[/tex] minutes and [tex]\(\frac{75}{100}\)[/tex] minutes, which is 45 seconds.

Now, Carol danced for 8 minutes and 12 seconds less than the combined time of Sue and Allie. We need to subtract this time from the total time Sue and Allie danced:

[tex]\(38\)[/tex] minutes and [tex]\(45\)[/tex] seconds [tex]\(-\) \(8\)[/tex] minutes and [tex]\(12\)[/tex] seconds.

Subtracting the minutes:

[tex]\(38 - 8 = 30\)[/tex] minutes.

Subtracting the seconds:

[tex]\(45 - 12 = 33\)[/tex] seconds.

Therefore, Carol danced for 30 minutes and 33 seconds. Since Sue and Allie's combined time was 38 minutes and 45 seconds, and Carol danced for 8 minutes and 12 seconds less, the total time the girls danced altogether is:

[tex]\(38\)[/tex] minutes and [tex]\(45\)[/tex] seconds [tex]\(-\) \(8\)[/tex] minutes and [tex]\(12\)[/tex] seconds [tex]\(=\) \(30\)[/tex] minutes and [tex]\(33\)[/tex] seconds.

Thus, the girls danced for a total of 30 minutes and 33 seconds.

What is the equation of the line that passes through the points (2,-1) and (6,1)?

Answers

The answer is y=1/2x-2

A recipe for cake needs to 1/4 cup of cake you are making 1/2 of the recipe how many cups of flour do you need?

Answers

Answer:

1/8

Step-by-step explanation:

If you need 1/4 cup for the full recipe and you're making half, you have to divide 1/4 by 2. Dividing 1/4 by 2 is the same as multiplying 1/4 by 1/2 since you take the reciprocal (opposite or flip) of 2. 1/4 times 1/2 is 1/8. I hope this helps!

Answer:

1/8

Step-by-step explanation

(1/4)÷2 is the same as saying (1/4)×(1/2)

Multiply the numerators (1×1)

Multiply the denominator (4×2)

and you get (1/8)

the slope of the line below -5 which of ths following is the point slope form of the line?​

Answers

The right answer is y + 8= -5 (x-2).

Answer:

[tex]y+8=-5(x-2)[/tex]

Step-by-step explanation:

Slope of the line =-5

To get point slope form of the line , we use the point that passes through the line. LEts pick the point (2,-8)

Point slope form of a line is

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

(x1,y1) is (2,-8) and slope m = -5

[tex]y-(-8)=-5(x-2)[/tex]

[tex]y+8=-5(x-2)[/tex] is the equation of the line in point slope form.

Write an addition equation or a subtraction equation to describe the diagram

Answers

The addition equation or a subtraction equation to describe the diagram is (-9)—(-4) = -13

What is an arithmetic operation?

It is defined as the operation in which we do the addition of numbers, subtraction, multiplication, and division. It has a basic four operators that is +, -, ×, and ÷.

We have a line graph shown in the picture.

The small arrow represents the length of 4 but as it is indicating negative direction, so we take -4

Similarly, the big arrow represents the length of 9 as it is indicating negative direction, so we take -9

The sum of the lengths:

(-9)—(-4) = -13

Thus, the addition equation or a subtraction equation to describe the diagram is (-9)—(-4) = -13

Learn more about the arithmetic operation here:

brainly.com/question/20595275

#SPJ2

what is perfect square trinomials
(x+4)^2=​

Answers

Answer:

x² + 8x + 16

Step-by-step explanation:

(x + 4)² = (x + 4)(x + 4)

Each term in the second parenthesis is multiplied by each term in the first parenthesis, that is

x(x + 4) + 4(x + 4) ← distribute both parenthesis

= x² + 4x + 4x + 16 ← collect like terms

= x² + 8x + 16 ← perfect square trinomial

Solve Y-37 equals 82

Answers

you can use inverse operations and add 37 to 82 and get y=119

Y= 119 because if you add 82 and 37 you get 119

To check: 119-37=82

Solve the inequality 3(x-1)<-3(2-2x)

Answers

i believe the answer would be x > 1?

Answer:

x > 1

Step-by-step explanation:

3(x-1)<-3(2-2x)

=> 3x +3 < 6x

=> 1<x

solve for X

(5x-2)^2=17

Answers

Answer:

hello : x = 2 +√17    or  x = 2 -√17

Step-by-step explanation:

(5x-2)^2=17

5x-2 = √17     or 5x-2 =  - √17

x = 2 +√17    or  x = 2 -√17

Apex Help!!!! At the beginning of year 1, Gracie invest $350 at annual simple interest rate of 4%. She makes no deposits to or withdrawals from the account

Answers

It's B A(n)= 350 + (n - 1) (0.04 · 350); $504.00

Answer:

Option B.

Step-by-step explanation:

Gracie invest $350 at the beginning of the year 1 at annual simple interest rate of 4%.

the balance at the beginning of the year 12. Interest will be calculated for 11 years.

Formula for simple interest : A = P(1 + rt)

By putting the value : A = 350(1 + 0.04 × 11)

                                   A = 350 ( 1.44 ) = $504.00

So the best answer would be option B.

The graph below shows three different normal distributions which statement must be true

Answers

Answer:

4th option is correct; Each distribution has a different mean and a different standard deviation

Step-by-step explanation:

For the mean to be same in all three distributions, all graphs must be centered around the same number, so mean is not same.

The width of each graph shows how much data deviate from the mean. Since the width is different in all three distributions, standard deviation is different in all three distributions

Answer:

D

Step-by-step explanation:

E2020

Other Questions
What hormone regulates the formation of urine A fast food restaurant sells burgers, chicken sandwiches, and entree salads. If a customer buys a burger, the probability they buy french fries is 0.80. Fifty percent of customers who purchase a chicken sandwich also buy fries, but only 10% of those buying an entree salad buy fries. Of all customers, 65% buy a burger, 20% a chicken sandwich, the rest buy an entree salad.What proportion of customers get a burger and fries? What is weight training A. a non competitive method of training that increases the rate at which muscles contract and relax B. A non competitive method of training to improve muscular strength and endurance Which expression is equal to (f - g)(x)? La raza Unida was a A triangle has angles measuring 15 degrees and 45 degrees what is the measure of the 3rd triangles 3rd angle? Which of the following points is a solution to the system of equations shown? x + y = -5 and 4x + y = 1(2,-7)(7,12)(4, -5) all vertebrates are____ a. endotherms,b. chordates, c.ectotherms, d. echinodermata which sentence describes a possible impact of early hunter gatherer societies on the environment? a. cultivating too many plants drained the land of water.b. introducing non-native species led to the extinction of some plants.c. overhunting led to the extinction of large herbivores species.d. reliance on fossil fuels polluted air, water, and land. PLEASE HELP ASAP!!! CORRECT ANSWER ONLY PLEASE!!! I CANNOT RETAKE THIS AND I NEED ALL CORRECT ANSWERS ONLY!!!The following symbol is used to represent ____ in a circuit diagram. which is a prime number 7 63 33 27 The first question a student formulates while determine a research paper topic should be A) an expansion of the information read B) concretely answered C) opinion orientated D) interesting to read which type of fats may help lower your risk of heart disease name three other countries besides the United states where revolution wars for independence were taking place towards the end of the eighteenth and beginning of the nineteenth century. W.W. Jacobs uses mainly _____ in The Monkeys Paw.A - ethosB - logosC - pathosD - a combination of logos and ethos a tree 24 feet tall casts a shadow 12 feet long. Brad is 6 feet tall. How long is Brad's shadow? draw a diagram and solve For your instagram ad, you will be paying 80 cents per click.You get 3,320 clicks what is your cost? If the petals of a flower are reduced how is the plant pollinated Mr. Ornelas needed to travel 400 miles to reach Chicago from hishome. He went to Chicago in 8 hours and came back at an average speedof 52 miles per hour. Which part of his trip was faster and how do youknow? What was done to the linear parent function f(X) = x to get the function g(x) = 1/5xA. Horizontally compressed by a factor of 5B. Vertically stretched by a factor of 5C. Shifted 1/5 unit upD. Vertically compressed by a factor of 5