How many terms of the series 2 + 5 + 8 + … must be taken if their sum is 155

Answers

Answer 1

9514 1404 393

Answer:

  10

Step-by-step explanation:

The sum of terms of an arithmetic series is ...

  Sn = (2a +d(n -1))·n/2 = (2an +dn^2 -dn)/2

For the series with first term 2 and common difference 3, the sum is 155 for n terms, where ...

  155 = (3n^2 +n(2·2 -3))/2

Multiplying by 2, we have ...

  3n^2 +n -310 = 0 . . . . . arranged in standard form

Using the quadratic formula, the positive solution is ...

  n = (-1 +√(1 -4(3)(-310)))/(2(3)) = (-1 +√3721)/6 = (61 -1)/6 = 10

10 terms of the series will have a sum of 155.

Answer 2
Answer: 10 terms

Step-by-step explanation:

[tex]\displaystyle \ \Large \boldsymbol{} S_n=\frac{2a_1+d(n-1)}{2} \cdot n =155 \\\\ \frac{4+3(n-1)}{2} \cdot n =155 \\\\\\ 4n+3n^2-3n=310 \\\\ 3n^2+n-310=0 \\\\D=1+3720=3721=61^2\\\\n_1=\frac{61-1}{6} =\boxed{10} \\\\\\n_2=\frac{-61-1}{3} \ \ \o[/tex]


Related Questions

PLZ ANSWER QUESTION IN PICTURE

Answers

Answer: [tex]y=\frac{1}{3}x+\frac{13}{3}[/tex]

Step-by-step explanation:

(slope = m)

[tex]m=\frac{y_2-y_1}{x_2-x_1}=\frac{4-6}{-1-5}=\frac{-2}{-6}=\frac{1}{3}[/tex]

[tex]y=mx+b, (5,6), (-1,4), m=\frac{1}{3}[/tex]

[tex]y=mx+b\\6=\frac{1}{3}(5)+b\\b=6-\frac{5}{3} \\b=\frac{13}{3}\\y=\frac{1}{3}x+\frac{13}{3}[/tex]

Ivan drove 335 miles in 5 hours.
At the same rate, how long would it take him to drive 737 miles?
hours
Х
?

Answers

Answer: x= 11

Step-by-step explanation:

To answer the question, we first need to know how many miles he/she/it can drive in one hour (to make it simpler. Doing a bunch of calculations involving decimals and other stuff can be very confusing)

335 divided by 5 is 67

Therefore in one hour Ivan can drive 67 miles. We want to know the TIME it takes for Ivan to drive 737 miles and the formula for time is Distance / Speed.

The distance is 737 miles

The speed is 67 miles/hour

737 divided by 67 is 11

Therefore Ivan takes 11 hours to drive 737 hours

A population is equally divided into three class of drivers. The number of accidents per individual driver is Poisson for all drivers. For a driver of Class I, the expected number of accidents is uniformly distributed over [0.2, 1.0]. For a driver of Class II, the expected number of accidents is uniformly distributed over [0.4, 2.0]. For a driver of Class III, the expected number of accidents is uniformly distributed over [0.6, 3.0]. For driver randomly selected from this population, determine the probability of zero accidents.

Answers

Answer:

Following are the solution to the given points:

Step-by-step explanation:

As a result, Poisson for each driver seems to be the number of accidents.

Let X be the random vector indicating accident frequency.

Let, [tex]\lambda=[/tex]Expected accident frequency

[tex]P(X=0) = e^{-\lambda}[/tex]

For class 1:

[tex]P(X=0) = \frac{1}{(1-0.2)} \int_{0.2}^{1} e^{-\lambda} d\lambda \\\\P(X=0) = \frac{1}{0.8} \times [-e^{-1}-(-e^{-0.2})] = 0.56356[/tex]

For class 2:

[tex]P(X=0) = \frac{1}{(2-0.4)} \int_{0.4}^{2} e^{-\lambda} d\lambda\\\\P(X=0) = \frac{1}{1.6} \times [-e^{-2}-(-e^{-0.4})] = 0.33437[/tex]

For class 3:

[tex]P(X=0) = \frac{1}{(3-0.6)} \int_{0.6}^{3} e^{-\lambda} d\lambda\\\\P(X=0) = \frac{1}{2.4} \times [-e^{-3}-(-e^{-0.6})] = 0.20793[/tex]

The population is equally divided into three classes of drivers.

Hence, the Probability

[tex]\to P(X=0) = \frac{1}{3} \times 0.56356+\frac{1}{3} \times 0.33437+\frac{1}{3} \times 0.20793=0.36862[/tex]

Given the function h(t) = 2t to the power of 2 + 9 evaluate h(5)

Answers

9514 1404 393

Answer:

  59

Step-by-step explanation:

Put 5 where t is and do the arithmetic.

  [tex]h(t)=2t^2+9\\\\h(5)=2\cdot5^2+9=2\cdot25+9\\\\\boxed{h(5)=59}[/tex]

Help with 5b please . thank you.​

Answers

Answer:

See explanation

Step-by-step explanation:

We are given f(x)=ln(1+x)-x+(1/2)x^2.

We are first ask to differentiate this.

We will need chain rule for first term and power rule for all three terms.

f'(x)=(1+x)'/(1+x)-(1)+(1/2)×2x

f'(x)=(0+1)/(1+x)-(1)+x

f'(x)=1/(1+x)-(1)+x

We are then ask to prove if x is positive then f is positive.

I'm thinking they want us to use the derivative part in our answer.

Let's look at the critical numbers.

f' is undefined at x=-1 and it also makes f undefined.

Let's see if we can find when expression is 0.

1/(1+x)-(1)+x=0

Find common denominator:

1/(1+x)-(1+x)/(1+x)+x(1+x)/(1+x)=0

(1-1-x+x+x^2)/(1+x)=0

A fraction can only be zero when it's numerator is.

Simplify numerator equal 0:

x^2=0

This happens at x=0.

This means the expression,f, is increasing or decreasing after x=0. Let's found out what's happening there. f'(1)=1/(1+1)-(1)+1=1/2 which means after x=0, f is increasing since f'>0 after x=0.

So we should see increasing values of f when we up the value for x after 0.

Plugging in 0 gives: f(0)=ln(1+0)-0+(1/2)0^2=0.

So any value f, after this x=0, should be higher than 0 since f(0)=0 and f' told us f in increasing after x equals 0.

Jason can peel 15 potatoes in 25 minutes. Janette can peel 8 potatoes in 1/10 hour. If they start peeling at the same time how many
minutes will it take them to peel 406 potatoes?

Answers

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Answer:

  210 minutes

Step-by-step explanation:

Jason's rate of peeling is ...

  (15 potatoes)/(25 minutes) = 15/25 potatoes/minute = 3/5 potatoes/minute

Janette's rate of peeing potatoes is ...

  (8 potatoes)/(6 minutes) = 4/3 potatoes/minute

Their combined rate is ...

  (3/5 +4/3) = (9 +20)/15 = 29/15 . . . . potatotes/minute

Then the time required for 406 potatoes is ...

  (406 potatoes)/(29/15 potatoes/minute) = (406×15/29) minutes

  = 210 minutes

Determine a scalar c so that the angle between a = i + cj and b = i + j is 45°.​

Answers

Answer:

c=0

Step-by-step explanation:

ATQ a.b=|a||b|sin(45)

1+c=sqrt(1+c^2)*sqrt(2)*1/sqrt(2)

1+c=sqrt(1+c^2)

(1+c)^2=(1+c^2)

2c=0, c=0

The required simplified value of c is zero for which the angle between a and b is 45°.

What is a vector?

Vector is defined as the quantities that have both magnitude and direction are called a vector quantity and the nature of the quantity is called a vector.  

Here,
scaler product is given as,
a . b = |a|.|b|cos45
(i + cj). (i + j) = √[1² + c²] . √[1²+1²] × 1/√2
1 + c = √1 + c²

Squaring both sides
(1 + c)² = 1 + c²
1 + c² + 2c =1 + c²
2c = 0
c = 0

Thus, the required simplified value of c is zero for which the angle between a and b is 45°.

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In the figure, find the measure of TU⎯⎯⎯⎯⎯⎯⎯⎯

Answers

Answer:

TU = 27

Step-by-step explanation:

We are given two secant segments that are drawn from a circle to meet at an exterior point of the circle. Thus, according to the secant secant theorem, the product of the measure of one secant segment and its external secant segment equals that of the product of the other and its external secant segment.

Thus:

VU*TU = VW*BW

Substitute

7(x + 4) = 9(-2 + x)

7x + 28 = -18 + 9x

Collect like terms

7x - 9x = -18 - 28

-2x = -46

Divide both sides by -2

x = -46/-2

x = 23

✔️TU = x + 4

Plug in the value of x

TU = 23 + 4

TU = 27

A telephone service representative believes that the proportion of customers completely satisfied with their local telephone service is different between the South and the Midwest. The representative's belief is based on the results of a survey. The survey included a random sample of 1300 southern residents and 1380 midwestern residents. 39% of the southern residents and 50% of the midwestern residents reported that they were completely satisfied with their local telephone service. Find the 80% confidence interval for the difference in two proportions. Step 1 of 3 : Find the point estimate that should be used in constructing the confidence interval

Answers

Answer:

The point estimate that should be used in constructing the confidence interval is 0.11.

The 80% confidence interval for the difference in two proportions is (0.0856, 0.1344).

Step-by-step explanation:

Before building the confidence interval, we need to understand the central limit theorem and subtraction of normal variables.

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.

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]

Subtraction between normal variables:

When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.

Midwest:

50% of 1380, so:

[tex]p_M = 0.5[/tex]

[tex]s_M = \sqrt{\frac{0.5*0.5}{1380}} = 0.0135[/tex]

South:

39% of 1300, so:

[tex]p_S = 0.39[/tex]

[tex]s_S = \sqrt{\frac{0.39*0.61}{1300}} = 0.0135[/tex]

Distribution of the difference:

[tex]p = p_M - p_S = 0.5 - 0.39 = 0.11[/tex]

So the point estimate that should be used in constructing the confidence interval is 0.11.

[tex]s = \sqrt{s_M^2+s_S^2} = \sqrt{0.0135^2+0.0135^2} = 0.0191[/tex]

Confidence interval:

[tex]p \pm zs[/tex]

In which

z is the z-score that has a p-value of [tex]1 - \frac{\alpha}{2}[/tex].

80% confidence level

So [tex]\alpha = 0.2[/tex], z is the value of Z that has a p-value of [tex]1 - \frac{0.2}{2} = 0.9[/tex], so [tex]Z = 1.28[/tex].  

The lower bound of the interval is:

[tex]p - zs = 0.11 - 1.28*0.0191 = 0.0856[/tex]

The upper bound of the interval is:

[tex]p + zs = 0.11 + 1.28*0.0191 = 0.1344[/tex]

The 80% confidence interval for the difference in two proportions is (0.0856, 0.1344).

A simple random sample of 400 individuals provides 112 Yes responses. (a) What is the point estimate of the proportion of the population that would provide Yes responses

Answers

Answer:

The point estimate of the proportion of the population that would provide Yes responses is 0.28.

Step-by-step explanation:

Point estimate of the proportion of the population that would provide Yes

The sample proportion of yes responses.

In the sample:

112 yes responses in the sample of 400, so:

[tex]p = \frac{112}{400} = 0.28[/tex]

The point estimate of the proportion of the population that would provide Yes responses is 0.28.

What is the formula for the volume of a pyramid?

V = πr2h
V = 3/4πr2h
V = 1/3πr2h
V = 1/3Bh

Answers

Which behavior would best describe someone who has good communication skills with customers ? a) Following up with some customers b) Talking to customers more than listening to them c) Repeating back what the customer says d) Interrupting customers frequently
The formula is V=1/3Bh

Which of the following is a solution to 6x - 5y=4?
(2,7)
(-1, -2)
(-2, -1)
(2, -7)

Answers

Answer:

2,7

Step-by-step explanation:

Answer:

(-1,-2)

Step-by-step explanation:

(6 x -1) -(-2 x 5) = 4

-6 + 10 = 4

The whole number 23 is an example of a ____ number.

prime or composite?

Answers

The answer is prime! I hope this helps you out!

Answer:

23 is a prime number. Reason: Prime number are those numbers which are divisible by 1 and itself. Example: 5 is divisible by 1 and 5 only.

Which is a graph of g(c) = (0.5)x+3^ -4

Answers

Answer:

I've attached a graph with this, that's your answer

Find the measure of angle FGE
35 degrees
40 degrees
100 degrees
30 degrees
60 degrees

Answers

The answer is 35 degrees.

The measure of angle FGE is 52.5°.

What is the Angles of Intersecting Secants Theorem?

Angles of Intersecting Secants Theorem states that, If two lines intersect outside a circle, then the measure of an angle formed by the two lines is one half the positive difference of the measures of the intercepted arcs.

Thus, applying the angles of intersecting secants theorem

m∠FGE = 1/2[(100 + 35) - 30]

m∠FGE = 1/2[(105]

m∠FGE = 52.5°

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What is distributive property???

Answers

A number multiplied by a sum is the same as the sum of the number multiplied by each addend; a(b + c) = ab + ac

Answer:

the distributive property of binary operations generalizes the distributive law from elementary algebra, which asserts that one has always For example, one has One says that multiplication distributes over addition.

helpppp asap pleaseee

Answers

Answer:

29/3 is your answer

Step-by-step explanation:

pls mark as brainliest

Instructions: The polygons in each pair are similar. Find the
missing side length.

Answers

Answer:

missing side length is 12

Step-by-step explanation:

similar means that all correlating pairs of sides have the same ratio (old side length) / (new side length).

so, when we know the ratio of one pair, we can apply it to any other side to calculate the correlating side.

we see, when we go from small to large, that we have the ratio 32/40 = 4/5.

so, multiplying the larger side by this, we get the shorter side.

15 × 4/5 = 3 × 4 = 12

the proportion part in your picture is a bit confusing :

yes,

x/15 = 32/40 = 32/40

I don't know, why this last expression was repeated.

x/15 = 32/40

x = 15×32/40 = 15×4/5 = 3×4 = 12

as you see we get of course the same result doing it that way.

3) Consider the sequence -11 ; 2sin3x ; 15; ...

3.1.1) Determine the values of x in the interval [0 ; 90] for whichthe sequence will be arithmetic.​

Answers

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Answer:

  x = 30

Step-by-step explanation:

In an arithmetic sequence, any given term is the average of the two terms that come before and after. The middle term of this sequence must be ...

  2sin(3x) = (-11 +15)/2

  sin(3x) = 1 . . . . . . . . . . simplify and divide by 2

Then the value of 3x must be 90°, so ...

  x = 90/3 = 30

There is one value of x in the interval [0, 90] that makes this sequence arithmetic: x = 30.

Help me please with this question

Answers

9514 1404 393

Answer:

  21

Step-by-step explanation:

Let c represent the number of child tickets sold. Then 2c is the number of adult tickets sold. The total revenue is ...

  5.80c +9.50(2c) = 520.80

  24.80c = 520.80 . . . . . . . . . simplify

  c = 21 . . . . . . . . . . . . . . divide by 24.80

21 child tickets were sold that day.

A 10​-sided die is rolled. Find the probability of rolling an even number. The set of equally likely outcomes is shown below. ​{1, 2, 3, 4, 5, 6, 7, 8, 9, 10​}

The probability of rolling an even number on a 10​-sided die is:

Answers

Answer:

1/2

Step-by-step explanation:

There are ten sides on this die. As stated in your question, there are five even numbers and five odd numbers. If we take the amount of even numbers over the total, you get 5/10, which simplifies to 1/2.

The probability of rolling an even number on a 10 - sided die is 1/2 or 0.5

What is Probability?

The probability that an event will occur is measured by the ratio of favorable examples to the total number of situations possible

The value of probability lies between 0 and 1

Given data ,

Let the data set be S = { 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ​}

So , the number of elements in the data set = 10 elements

Now , in order to get an even number when dolling the dice ,

The set of possible outcomes P = { 2 , 4 , 6 , 8 , 10 }

The number of elements in the data set P of outcomes = 5 elements

So , the probability of getting an even number from the data set when rolling a 10 sided dice is P ( x ) =
number of elements in the data set P of outcomes / number of elements in the data set

The probability of getting an even number from the data set when rolling a 10 sided dice is P ( x ) = 5 / 10

The probability P ( x ) = 1/2

                                   = 0.5

Hence , The probability of rolling an even number on a 10 - sided die is 1/2 or 0.5

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Find the length of the arc.
A. 21/π4 in
B. 18π in
C. 45/π8 in
D. 1890π in

Answers

Answer:

we know that all Lenght of circle is 2πr so 2*π*7=14π

Step-by-step explanation:

14π equal to 360°

but we need just 135° so we should write it kind of radian(π)

if 14π=360°

x=135°

14π*135=360°*x 14π*27=72*x ........= 14π*3=8*x

7π*3=4*x ....... X=21π/4

The length of the arc is 21/π4 in

An answer is an option A. 21/π4 in

What is the arc of the circle?

The arc period of a circle can be calculated with the radius and relevant perspective using the arc period method.

⇒angle= arc/radius

 ⇒  135°=arc/7

⇒ arc =135°*7

  ⇒arc=135°*π/180° *7in

⇒arc = 21/π4 in

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A local cinema reduced its ticket prices by 15% which means a ticket now costs £10.88. how much was a ticket before the reduction?

Answers

Right now the ticket price is 85% of the original price. So the original price would be 10.88 / 0.85 = 13.6

Calculate the break even sales dollars if the fixed expenses are $7,000 and the contribution ratio is 40%.

Answers

Answer:

Break even sales = $17,500 (Approx.)

Step-by-step explanation:

Given:

Fixed expenses = $7,000

Contribution ratio = 40%

Find:

Break even sales dollars

Computation:

Break even sales = Fixed expenses / Contribution ratio

Break even sales = 7,000 / 40%

Break even sales = 7,000 / 0.40

Break even sales = 17,500

Break even sales = $17,500 (Approx.)

56 x 10^-4)
Group of answer choices

2.37 x 10^-16

4.21 x 10^15

2.4 x 10^-16

4.2 x 10^15

Answers

9514 1404 393

Answer:

  (d)  4.2×10^15

Step-by-step explanation:

Your calculator will tell you the quotient is about ...

  4.21348...×10^15

The least precise number in the division is 1.5, which has 2 significant digits. Therefore, the result should be rounded to 2 significant digits:

  4.2×10^15

The scatterplot shows the selling prices of homes and the square feet of living space.

A graph titled home value has square feet (thousands) on the x-axis, and price (hundred thousand dollars) on the y-axis. Points are at (1.2, 1), (1.5, 1.1), (2, 1.5), (2.5, 2). An orange point is at (3.8, 3.9).

Complete the statements based on the information provided.

The scatterplot including only the blue data points shows
✔ a strong positive
correlation. Including the orange data point at (3.8, 3.9) in the correlation would
✔ strengthen
and
✔ increase
the value of

Answers

Answer:

✔ a strong positive  

✔ strengthen  

✔ increase

ED2021

Answer:

- a strong positive

- strengthen

- increase

Use the discriminant to describe the roots of each equation. Then select the best description.
7x² + 1 = 5x

Answers

Answer:

Imaginary roots

Step-by-step explanation:

The discriminant of a quadratic in standard form [tex]ax^2+bx+c[/tex] is given by [tex]b^2-4ac[/tex].

Given [tex]7x^2+1=5x[/tex], subtract 5x from both sides so that the quadratic is in standard form:

[tex]7x^2-5x+1=0[/tex]

Now assign variables:

[tex]a\implies 7[/tex] [tex]b\implies -5[/tex] [tex]c\implies 1[/tex]

The discriminant is therefore [tex](-5)^2-4(7)(1)=25-28=\textbf{-3}[/tex].

What does this tell us about the roots?

Recall that the discriminant is what is under the radical in the quadratic formula. The quadratic formula is used to find the solutions of a quadratic. Therefore, the solutions of this quadratic would be equal to [tex]\frac{-b\pm \sqrt{-3}}{2a}[/tex] for some [tex]b[/tex] and [tex]a[/tex]. Since the number under the radical is negative, there are no real roots to the quadratic (whenever the discriminant is negative, the are zero real solutions to the quadratic). Therefore, the quadratic has imaginary roots.

Pls if anyone knows the answer with work included/steps that will be greatly appreciated :)

Answers

Answer:

3.  3x^2 + 15x

4.  x=36

Step-by-step explanation:

The area of a rectangle is

A = l*w

A = (3x)*(x+5)

Distribute

3x^2 + 15x

2/3x - 4 = 20

Add 4 to each side

2/3x -4+4 = 20+4

2/3x = 24

Multiply each side by 3/2

2/3*3/2 =24*3/2

x = 12*3

x=36

write any five sentences of fraction?​

Answers

Step-by-step explanation:

Fractions represent equal parts of a whole or a collection. 

Fraction of a whole: When we divide a whole into equal parts, each part is a fraction of the whole. 

a fraction has 2 parts

The number on the top of the line is called the numerator. It tells how many equal parts of the whole or collection are taken.  The number below the line is called the denominator.  It shows the total divisible number of equal parts the whole into or the total number of equal parts which are there in a collection. 

There are different types of fraction

unit fractionimproper fractionproper fractionmixed fraction

PLEASE HELP OR IM gonna FAILLLLLLLL!!!!!!!!

Answers

Answer:

C. 1/(4^10)

Step-by-step explanation:

Let's break it down: 4^-2 = 1/(4^2)(1/(4^2))^5 = (1^5)/(4^2)^5 = 1/(4^10)

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