Given:
The geometric sequence is:
[tex]n[/tex] [tex]a_n[/tex]
1 -4
2 20
3 -100
To find:
The explicit formula and list any restrictions to the domain.
Solution:
The explicit formula of a geometric sequence is:
[tex]a_n=ar^{n-1}[/tex] ...(i)
Where, a is the first term, r is the common ratio and [tex]n\geq 1[/tex].
In the given sequence the first term is -4 and the second term is 20, so the common ratio is:
[tex]r=\dfrac{a_2}{a_1}[/tex]
[tex]r=\dfrac{20}{-4}[/tex]
[tex]r=-5[/tex]
Putting [tex]a=-4,r=-5[/tex] in (i), we get
[tex]a_n=-4(-5)^{n-1}[/tex] where [tex]n\geq 1[/tex]
Therefore, the correct option is B.
The time for a visitor to read health instructions on a Web site is approximately normally distributed with a mean of 10 minutes and a standard deviation of 2 minutes. Suppose 64 visitors independently view the site. Determine the following: a. The expected value and the variance of the mean time of the visitors. b. The probability that the mean time of the visitors is within 15 seconds of 10 minutes c. The value exceeded by the mean time of the visitors with probability 0.01.
Answer:
a) The mean is 10 and the variance is 0.0625.
b) 0.6826 = 68.26% probability that the mean time of the visitors is within 15 seconds of 10 minutes.
c) 10.58 minutes.
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
Normal Probability Distribution
Problems of normal distributions can be solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
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.
Normally distributed with a mean of 10 minutes and a standard deviation of 2 minutes.
This means that [tex]\mu = 10, \sigma = 2[/tex]
Suppose 64 visitors independently view the site.
This means that [tex]n = 64, = \frac{2}{\sqrt{64}} = 0.25[/tex]
a. The expected value and the variance of the mean time of the visitors.
Using the Central Limit Theorem, mean of 10 and variance of (0.25)^2 = 0.0625.
b. The probability that the mean time of the visitors is within 15 seconds of 10 minutes.
15 seconds = 15/60 = 0.25 minutes, so between 9.75 and 10.25 seconds, which is the p-value of Z when X = 10.25 subtracted by the p-value of Z when X = 9.75.
X = 10.25
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{10.25 - 10}{0.25}[/tex]
[tex]Z = 1[/tex]
[tex]Z = 1[/tex] has a p-value of 0.8413.
X = 9.75
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{9.75 - 10}{0.25}[/tex]
[tex]Z = -1[/tex]
[tex]Z = -1[/tex] has a p-value of 0.1587.
0.8413 - 0.1587 = 0.6826.
0.6826 = 68.26% probability that the mean time of the visitors is within 15 seconds of 10 minutes.
c. The value exceeded by the mean time of the visitors with probability 0.01.
The 100 - 1 = 99th percentile, which is X when Z has a p-value of 0.99, so X when Z = 2.327.
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]2.327 = \frac{X - 10}{0.25}[/tex]
[tex]X - 10 = 2.327*0.25[/tex]
[tex]X = 10.58[/tex]
So 10.58 minutes.
Determine the probability of landing on tails at most 33 times if you flip a fair coin 80 times. Round your answer to the nearest tenth.
Answer:
0.0728177272
Step-by-step explanation:
Given :
Number of flips = 80
Probability of landing on tail at most 33 times ;
Probability of landing on tail on any given flip = 1 / 2 = 0.5
This a binomial probability problem:
Hence ;
P(x ≤ 33) = p(x=0) + p(x=1) +... + p(x = 33)
Using a binomial probability calculator :
P(x ≤ 33) = 0.0728177272
Consider the phrase "the sum of 3 times a number and the quotient of the number and 4." Let’s break it down. You want the sum of two values. The first value is 3 times a number. What expression represents 3 times a number?
9514 1404 393
Answer:
3x
Step-by-step explanation:
If x represents the number, then "3 times a number" is 3x.
__
Additional comment
"The quotient of the number and 4" is x/4.
The sum of those two expressions is ...
3x + x/4
Please help below with prob Stats
Answer:
te qif y btubf
Step-by-step explanation:
The scores on a standardized test are normally distributed with a mean of 80 and standard
deviation of 5. What test score is 0.9 standard deviations above the mean?
Answer:
84.5
Step-by-step explanation:
Given :
Mean μ = 80
Standard deviation, σ = 5
Z = number of standard deviations from the mean, Z = 0.9
Teat score, x
Using the Zscore formula :
Zscore = (x - μ) / σ
Plugging in our values :
0.9 = (x - 80) / 5
Cross multiply
0.9 * 5 = x - 80
4.5 = x - 80
4.5 + 80 = x
x = 84.5
Test score = 84.5
Which of the following is the solution set of 6x + 5 = -29? {-4}
Answer:
[tex]{ \tt{6x + 5 = - 29}} \\ { \tt{6x = - 36}} \\ { \tt{x = - 6}}[/tex]
Can someone help me? I am struggling and I would be so happy if any of you helped me. Thank you for your help.
Answer:
mean=256229+253657+218747+246163+235626+288694+316265+196721+285077+215152+253291+315011+199901+265443+291806+303556+215359+258554+293658+289935÷21
=5198845÷21
=247564.0
=247564 to the next whole number
B.6 times
Simplify
x * x^5 / x^2 * x
Hari earns Rs 4300 per month. He spends 80% from his income. How much amount does he save in a year?
Answer:
Hari saves $ 10,320 in a year.
Step-by-step explanation:
Given that Hari earns $ 4300 per month, and he spends 80% from his income, to determine how much amount does he save in a year, the following calculation must be performed:
100 - 80 = 20
4300 x 0.20 x 12 = X
860 x 12 = X
10320 = X
Therefore, Hari saves $ 10,320 in a year.
Find the sum of the geometric series given a1=−2, r=2, and n=8.
A. -510
B. -489
C. -478
D. 2
Answer:
A. -510
Step-by-step explanation:
We are given the variable values:
a = -2r = 2n = 8Geometric series formula:
[tex]s = \frac{a( {r}^{n} \times - 1) }{r - 1} [/tex]
Plugging in values we have:
[tex]s = \frac{ - 2( {2}^{8} - 1) }{2 - 1} [/tex]
Simplifying the equation we are left with:
[tex] \frac{ - 2(255)}{1} = - 510[/tex]
6. Solve for x: 3|x - 7| = 15
Please give steps! ❤️
3 | x - 7 | = 15
Divide both sides by 3
3 | x - 7 | ÷ 3 = 15 ÷ 3
| x - 7 | = 5
_________________________
" Reminder "
| a | = t ===》 a = + t OR a = - t
__________________________
| x - 7 | = 5
x - 7 = 5 ====》 x = 12
OR
x - 7 = - 5 ===》 x = 2
someone please help
Answer:
28
Step-by-step explanation:
78
If 4 gallons of gasoline cost $13.76, how much will 11 gallons of gasoline cost?
Answer:
x=37.84
Step-by-step explanation:
We can write a ratio to solve
4 gallons 11 gallons
--------------- = ----------------
13.76 x dollars
Using cross products
4x = 11*13.76
4x=151.36
Divide by 4
4x/4 = 151.36/4
x=37.84
Write the point-slope form of an equation of the line through the points (-2, 6) and (3,-2).
Answer:
[tex]y-6=-\frac{\displaystyle 8}{\displaystyle 5}(x+2)[/tex]
OR
[tex]y+2=-\frac{\displaystyle 8}{\displaystyle 5}(x-3)[/tex]
Step-by-step explanation:
Hi there!
Point-slope form: [tex]y-y_1=m(x-x_1)[/tex] where [tex](x_1,y_1)[/tex] is a point and [tex]m[/tex] is the slope
1) Determine the slope
[tex]m=\frac{\displaystyle y_2-y_1}{\displaystyle x_2-x_2}[/tex] where two given points are [tex](x_1,y_1)[/tex] and [tex](x_2,y_2)[/tex]
Plug in the given points (-2, 6) and (3,-2):
[tex]m=\frac{\displaystyle -2-6}{\displaystyle 3-(-2)}\\\\m=\frac{\displaystyle -8}{\displaystyle 3+2}\\\\m=-\frac{\displaystyle 8}{\displaystyle 5}[/tex]
Therefore, the slope of the line is [tex]-\frac{\displaystyle 8}{\displaystyle 5}[/tex]. Plug this into [tex]y-y_1=m(x-x_1)[/tex]:
[tex]y-y_1=-\frac{\displaystyle 8}{\displaystyle 5}(x-x_1)[/tex]
2) Plug in a point [tex](x_1,y_1)[/tex]
[tex]y-y_1=-\frac{\displaystyle 8}{\displaystyle 5}(x-x_1)[/tex]
We're given two points, (-2, 6) and (3,-2), so there are two ways we can write this equation:
[tex]y-6=-\frac{\displaystyle 8}{\displaystyle 5}(x-(-2))\\\\y-6=-\frac{\displaystyle 8}{\displaystyle 5}(x+2)[/tex]
OR
[tex]y-(-2)=-\frac{\displaystyle 8}{\displaystyle 5}(x-3)\\y+2=-\frac{\displaystyle 8}{\displaystyle 5}(x-3)[/tex]
I hope this helps!
If (-3)^-5 = 1/x, what is the value of x?
Answer:
-243
Step-by-step explanation:
(-3) (-3) (-3) (-3) (-3) = - 243
[tex]\frac{1}{-243 }[/tex]
A bag contains 9 red balls numbered 1, 2, 3, 4, 5, 6, 7, 8, 9 and 6 white balls numbered 10, 11, 12, 13, 14, 15. One ball is drawn from the bag. What is the probability that the ball is white, given that the ball is even-numbered
Answer:
3/ 7
Step-by-step explanation:
We know that it is an even ball
2,4,6,8,10,12,14 are even balls
2,4,6,8 are red and 10,12,14 are white
P ( white) = white even / total even
= 3/ 7
HELP PLEASE I DONT KNOW THIS ONE
Answer:
-3x^2 +7x -4
-------------------------------
(x-3)(x-2)(x+3)
Step-by-step explanation:
2 3x
-------- - ----------
X^2-9 x^2 -5x+6
Factor
2 3x
-------- - ----------
(x-3)(x+3) (x-3)(x-2)
Get a common denominator
2 (x-2) 3x(x+3)
-------- - ----------
(x-3)(x+3)(x-2) (x-3)(x-2)(x+3)
2x-4 - (3x^2 -9x)
-------------------------------
(x-3)(x-2)(x+3)
Distribute
2x-4 - 3x^2 +9x
-------------------------------
(x-3)(x-2)(x+3)
Combine like terms
-3x^2 +7x -4
-------------------------------
(x-3)(x-2)(x+3)
[tex]\boxed{\large{\bold{\textbf{\textsf{{\color{gold}{Answer \red{:)}}}}}}}}[/tex]
[tex]\sf{\dfrac{2}{ x^2-9}-\dfrac{3x}{x^2-5x+6}}[/tex] [tex]\sf{\dfrac{2}{ (x)^2-(3)^2}-\dfrac{3x}{x^2-2x-3x+6} }[/tex] [tex]\sf{\dfrac{2}{(x+3)(x-3)}-\dfrac{3x}{x(x+2)-3(x+2)} }[/tex][tex]\sf{\dfrac{2}{(x+3)(x-3)}-\dfrac{3x}{(x+2)(x-3)}}[/tex][tex]\sf{\dfrac{2(x-2)-3x(x+3)}{(x+3)(x-2)(x-3)} }[/tex] [tex]\sf{\dfrac{2x-4-(3x^2-9x)}{(x+3)(x-2)(x-3) }}[/tex] [tex]\sf{\dfrac{2x-4-3x^2+9x}{(x+3)(x-2)(x-3) }}[/tex] [tex]\sf{\dfrac{-3x^2+7x-4}{(x+3)(x-2)(x-3) }}[/tex][tex]\sf{ }[/tex]
[tex]\sf{ }[/tex]
[tex]\sf{ }[/tex]
[tex]\sf{ }[/tex]
[tex]\sf{ }[/tex]
[tex]\sf{ }[/tex]
[tex]\sf{ }[/tex]
The function f(x)=log4x is dilated to become g(x)=f(13x).
What is the effect on f(x)?
Answer:
f(x) is compressed horizontally
Step-by-step explanation:
Given
[tex]f(x) = \log(4x)[/tex]
[tex]g(x) = f(13x)[/tex]
Required
The effect on f(x)
[tex]g(x) = f(13x)[/tex] implies that f(x) is horizontally compressed by 13.
So, we have:
[tex]f(13) = \log(4 * 13x)[/tex]
[tex]f(13) = \log(52x)[/tex]
So:
[tex]g(13) = \log(52x)[/tex]
Find the sample correlation coefficient for the following data.
X Y
3 8
7 12
5 13
9 10
11 17
13 23
19 39
21 38
a. .8911.
b. .9132.
c. .9822.
d. .9556.
Answer:
quneotentendeiporoqenouteetendxdin
Step-by-step explanation:
Write 4 with denominator 5
Answer:
4/5
Step-by-step explanation:
I'm not exactly sure what this question is asking but I'm guessing it's asking to create a fraction with the numerator as 4 and denominator as 5.
As part of a statistics project, a teacher brings a bag of marbles containing 500 white marbles and 400 red marbles. She tells the students the bag contains 900 total marbles, and asks her students to determine how many red marbles are in the bag without counting them. A student randomly draws 100 marbles from the bag. Of the 100 marbles, 45 are red. The data collection method can best be described as
Answer:
Survey
Step-by-step explanation:
During data collection for a particular study, reaching all target Population might seem illogical or impossible. Therefore, a subset of the population of interest is chosen and the outcome used to infer about the population. This procedure could be referred to a a SURVEY. In the scenario samples drawn from the population of interest is used to make inference on population. During a survey, selected data ponuts or subjects must be drawn at random in other to ensure that it is representative of the larger population data.
Two sides of a triangle have the same length. The third side measures 5 m less than twice the common length. The perimeter of the triangle is 23 m. What are the lengths of the three sides?
What is the length of the two sides that have the same length?
Answer:
Length of all 3 sides: 7, 7, and 9
Length of the two sides that have the same length: 7
Step-by-step explanation:
Let the two sides with equal lengths have a length of [tex]x[/tex]. We can write the third side as [tex]2x-5[/tex].
The perimeter of a polygon is equal to the sum of all its sides. Since the perimeter of the triangle is 23 meters, we have the following equation:
[tex]x+x+2x-5=23[/tex]
Combine like terms:
[tex]4x-5=23[/tex]
Add 5 to both sides:
[tex]4x=28[/tex]
Divide both sides by 4:
[tex]x=\frac{28}{4}=\boxed{7}[/tex]
Therefore, the three sides of the triangle are 7, 7, and 9 and the length of the two sides that have the same length is 7.
What is the true solution to the equation below? 2 lne^ln2x-lne^ln10x=ln30
It looks like the equation is
[tex]2\ln\left(e^{\ln(2x)}\right)-\ln\left(e^{\ln(10x)}\right) = \ln(30)[/tex]
Right away, we notice that any solution to this equation must be positive, so x > 0.
For any base b, we have [tex]b^{\log_b(a)}=a[/tex], so we can simplify this to
[tex]2\ln(2x)-\ln\left(10x\right) = \ln(30)[/tex]
Next, [tex]\ln(a^b)=b\ln(a)[/tex], so that
[tex]\ln(2x)^2-\ln\left(10x\right) = \ln(30)[/tex]
[tex]\ln\left(4x^2\right)-\ln\left(10x\right) = \ln(30)[/tex]
Next, [tex]\ln\left(\frac ab\right)=\ln(a)-\ln(b)[/tex], so that
[tex]\ln\left(\dfrac{4x^2}{10x}\right) = \ln(30)[/tex]
For x ≠ 0, we have [tex]\frac xx=1[/tex], so that
[tex]\ln\left(\dfrac{2x}5\right) = \ln(30)[/tex]
Take the antilogarithm of both sides:
[tex]e^{\ln\left((2x)/5\right)} = e^{\ln(30)}[/tex]
[tex]\dfrac{2x}5 = 30[/tex]
Solve for x :
[tex]2x = 150[/tex]
[tex]\boxed{x=75}[/tex]
125. Albert surveyed a class of 25 students on sports. 5 kids love baseball. 7 kids love basketball. 10 kids
love football. How many students did not like baseball, basketball, or football?
25 students
12 students
22 students
3 students
Answer:
3 students
Step-by-step explanation:
since the total number of students is 25,when you add those that like baseball, basketball and football the total number must be 25 but in this case it's 22 meaning 2 student liked neither.
7+5+10+x=25
x=25-22
=3
I hope this helps
9 3/5 % as a decimal, rounded to 3 decimal places, is:
Answer:
0.054
Step-by-step explanation:
9 3/5% as a decimal is 0.054 (already to 3 decimal places)
Answer from Gauthmath
9 are just, well..., 9
3/5 are 0.6
because 1/5 is 0.2
so it's 9.6%, not so complicated I guess
You wish to create a 5 digit number from all digits; 0 1 2 3 4 5 6 7 8 9
Repetition is not allowed
* 0 cannot be first as it does not count as a place value if it is first. Ie. 027 is a 2 digit number
How many even numbers can you have?
Answer:
10234
Step-by-step explanation:
one is the smallest number so its first
and then you can place zero
after that just place the second smallest number
and so on
Identify the possible rational roots for the equation x^4-3x^2+6=0
Answer:
[tex]6, -6, 3, -3, 2, -2, 1, -1[/tex]
Step-by-step explanation:
One is given the following equation, and the problem asks one to identify the rational roots of the equation:
[tex]x^4-3x^2+6=0[/tex]
The rational root theorem states that the list of positive and negative factors of the constant term over the factors of the coefficients of the term to the highest degree will yield a list of the rational roots of the equation. Use this theorem to generate a list of all possible ration roots of the equation.
[tex](+-)\frac{6,3,2,1}{1}[/tex]
Now rewrite this list in a numerical format:
[tex]6, -6, 3, -3, 2, -2, 1, -1[/tex]
This is the list of the possible rational roots. One has to synthetically divide each of these numbers by the given polynomial equation to find the actual rational roots. However, the problem only asks for the possible rational roots, not the actual rational roots, thus, this is not included.
How many counting numbers have three distinct nonzero digits such that the sum of the three digits is 7?
Answer:
6
Step-by-step explanation:
You have 2 conditions.
1. The digits must be different.
2. The digits must add to 7.
There aren't very many
124
142
214
241
412
421
That's it. That's your answer. There are 6 of them
The triangles are similar.
What is the value of x?
Enter your answer in the box.
x =
Answer:
x=12
Step-by-step explanation:
each side of the smaller triangle, we can multiply by 4 to get the side of the larger triangle
ex: 8*4=32 and 17*4=68
so we can assume that 15*4= 4x+12
60=4x+12
48=4x
x=12
Answer:
x = 12
Step-by-step explanation:
The triangles are similar so we can use ratios
4x+12 32
------- = ------------
15 8
Using cross products
(4x+12) *8 = 15 * 32
(4x+12) *8 = 480
Divide each side by 8
(4x+12) *8/8 = 480/8
4x+12 = 60
Subtract 12 from each side
4x+12 -12 = 60-12
4x = 48
Divide by 4
4x/4 = 48/4
x = 12
The midpoint of a segment is (6,−4) and one endpoint is (13,−2). Find the coordinates of the other endpoint.
A. (-1, -6)
B. (-1, 0)
C. (20, -6)
D. (20, 0)
Answer: A. (-1, -6)
Step-by-step explanation:
Use the midpoint formula:
Endpoint #1 = (x₁, y₁) = (13, -2)Endpoint #2 = (x₂, y₂)[tex]midpoint = (\frac{x_{1}+x_{2}}{2}, \frac{y_{1}+y_{2}}{2}) \\\\(6, -4) = (\frac{13+x_{2}}{2}, \frac{-2+y_{2}}{2})\\\\\frac{13+x_{2}}{2} =6\\\\13+x_{2}=6*2\\\\x_{2}=12-13=-1\\\\ \\ \frac{-2+y_{2}}{2}=-4\\\\-2+y_{2}=(-4)*2\\\\y_{2}=-8+2=-6\\\\\\\left \{ {{x_{2}=-1} \atop {y_{2}=-6}} \right.[/tex]
