Given:
The sum of the first three terms = 12
The sum of the first six terms = (−84).
To find:
The third term of a geometric progression.
Solution:
The sum of first n term of a geometric progression is:
[tex]S_n=\dfrac{a(r^n-1)}{r-1}[/tex]
Where, a is the first term and r is the common ratio.
The sum of the first three terms is equal to 12, and the sum of the first six terms is equal to (−84).
[tex]\dfrac{a(r^3-1)}{r-1}=12[/tex] ...(i)
[tex]\dfrac{a(r^6-1)}{r-1}=-84[/tex] ...(ii)
Divide (ii) by (i), we get
[tex]\dfrac{r^6-1}{r^3-1}=\dfrac{-84}{12}[/tex]
[tex]\dfrac{(r^3-1)(r^3+1)}{r^3-1}=-7[/tex]
[tex]r^3+1=-7[/tex]
[tex]r^3=-7-1[/tex]
[tex]r^3=-8[/tex]
Taking cube root on both sides, we get
[tex]r=-2[/tex]
Putting [tex]r=-2[/tex] in (i), we get
[tex]\dfrac{a((-2)^3-1)}{(-2)-1}=12[/tex]
[tex]\dfrac{a(-8-1)}{-3}=12[/tex]
[tex]\dfrac{-9a}{-3}=12[/tex]
[tex]3a=12[/tex]
Divide both sides by 3.
[tex]a=4[/tex]
The nth term of a geometric progression is:
[tex]a_n=ar^{n-1}[/tex]
Where, a is the first term and r is the common ratio.
Putting [tex]n=3,a=4,r=-2[/tex] in the above formula, we get
[tex]a_3=4(-2)^{3-1}[/tex]
[tex]a_3=4(-2)^{2}[/tex]
[tex]a_3=4(4)[/tex]
[tex]a_3=16[/tex]
Therefore, the third term of the geometric progression is 16.
A bag has 6695 blue marbles and 6696 red marbles. We repeatedly remove 2 marbles from the bag. If the two chosen marbles are of the same color then we put 1 new red marble in the bag (after removing the 2 chosen marbles). If the two marbles are of different colors then we put one new blue marble in the bag. What will be the color of the last marble in the bag
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Answer:
blue
Step-by-step explanation:
If two red marbles are removed, 1 red is returned. The number of reds is reduced by 1, and the number of blues is unchanged.
If two blue marbles are removed, 1 red is returned. The number of reds is increased by 1, and the number of blues is decreased by 2.
If one of each is removed, one blue is returned. The number of reds is reduced by 1, and the number of blues is unchanged.
So, at each step, the number of blue marbles is unchanged or reduced by 2. That is, it only changes by an even number. The number of blues is initially odd, so can never reach zero.
The last marble in the bag is blue.
Find the distance between the two points in simplest radical form. (-6,1) and (−8,−4)
Answer: 5
Step-by-step explanation: I think it is 5
How many boxes could you stack safely on a pallet if the pallet is 5 feet deep, five feet across, every box. is 1 x 1 and the maximum safe stacking height is 5 boxes? *
Answer:
25 boxes could be stacked safely on the pallet.
Step-by-step explanation:
To determine how many boxes could you stack safely on a pallet if the pallet is 5 feet deep, five feet across, every box is 1 x 1 and the maximum safe stacking height is 5 boxes, the following calculation should be performed:
Pallet = 5 x 5 = 25 square feet
Box = 1 x 1 = 1 square foot
25/1 = 25
Therefore, 25 boxes could be stacked safely on the pallet.
Last year Nancy weighted 37( 5)/(8) pounds. This year she weighed 42.7 pounds. How much did she gain?
Answer:
22.7 pounds
Step-by-step explanation:
Simply just subtract 42.7 with 37 (5/8) to get the answer. If done correctly, you should get 22.7 pounds.
So, the final answer is 22.7 pounds.
Hope this helped!
Identify the percent, amount, and base in this problem.
What percent of 80 is 40?
Answer:
50Step-by-step explanation:
40: 80x100 =100 =(40x100): 80 =100): 80 =4000: 80 = 50The percentage of the number 80 is 40 will be 50%.
What is the percentage?The amount of any product is given as though it was a proportion of a hundred. The ratio can be expressed as a quarter of 100. The phrase % translates for one hundred percent. It is symbolized by the character '%'.
The percentage is given as,
Percentage (P) = [Final value - Initial value] / Initial value x 100
The percentage is given as,
P = [(80 - 40) / 80] x 100
P = (40 / 80) x 100
P = 0.50 x 100
P = 50%
The percentage of the number 80 is 40 will be 50%.
More about the percentage link is given below.
https://brainly.com/question/8011401
#SPJ2
53:28
Nathan and Jordan design surveys to determine the average amount of time bicyclists in a race spend training each
week. Nathan surveys every fifth bicyclist crossing the finish line after a race. Jordan surveys the first five bicyclists to
finish the race. Which best explains which sample is likely to be the most valid?
Nathan's because his sample was more random
Jordan's because his sample was more random
Nathan's because his sample contained elements of the population
Jordan's because his sample contained elements of the population
Answer:
Nathan's because his sample was more random
Step-by-step explanation:
Nathan's survey could be described as a Systematic random sampling technique whereby every 5th observation taken as a sample from the population. With these technique we have a more random observation than with.
Answer:
C
Step-by-step explanation:
solve this fast please… and thank you so much :)
Answer:
hi
Step-by-step explanation:
ABCD is a square of side 12 cm. It is formed from two rectangles AEGD and
EBCG. H is a point on AD and F is a point on BC.
Find the area of EFGH.
Answer:72 [tex]cm^{2}[/tex]
Solution 1:
Step 1: Find EF use Pythagorean theorem
[tex]EF^{2} = EB^{2} + BF^{2}[/tex]
[tex]EF^{2} = 6^{2} + 6^{2}[/tex]
EF = [tex]\sqrt{6^{2} + 6^{2} }[/tex] = 6[tex]\sqrt{2}[/tex] cm
Step 2: The area of EFGH = [tex]EF^{2}[/tex]= [tex](6\sqrt{2} )^{2}[/tex] = 72
Solution 2: See that the area of EFGH is equal [tex]\frac{1}{2}[/tex] the area of ABCD
The area of ABCD = 12x12 = 144
Thus, the area of EFGH = 144: 2 = 72:)
Have a nice day!
Suppose your dean of admissions is considering surveying high school seniors about their perceptions of your school to design better informational brochures for them. What are the advantages and disadvantages of doing (a) telephone interviews and (b) an Internet survey of seniors who have requested information about the school
Answer and explanation:
Advantages of telephone interviews:
They are more convenient than face to face interviews
They are alot more cost-effective
There is a wider geographical access as you can reach people in other countries too
Disadvantages of telephone interviews:
Questions become has limited complexity as opposed to face to face interviews
It may be somewhat intrusive for customers and there could also be interference from noise in the background. Also bad connection issues.
Advantages of internet survey:
Increased geographical access leading to high response rate.
Alot more convenient and flexible than face to face interviews
Low cost advantages
Disadvantages of internet survey:
Inability for individuals who are not online to participate
Non response bias
Limited complexity of questions, usually close ended questions
An adult soccer league requires a ratio of at least 2 women per 7 men on the roster. If 14 men are on the roster, how many women are needed to maintain that ratio?
Answer:
Atleast 4 women
Step-by-step explanation:
Ratio of
Women to men = 2 : 7
Number of women needed to maintain the ratio if there are 14 men on the roster :
The minimum number of women required :
(2 : 7) * number of men in roster
(2 / 7) * 14
2 * 2 = 4 women
Atleast 4 women are required to main the ratio
Suppose 41% of the students in a university are baseball players. If a sample of 524 students is selected, what is the probability that the sample proportion of baseball players will be greater than 44%
Answer:
"0.0808" is the appropriate response.
Step-by-step explanation:
Given:
n = 524
[tex]\hat{P}[/tex] = 41%
or,
= 0.41
[tex]1-\hat{P}=1-0.41[/tex]
[tex]=0.59[/tex]
[tex]\mu \hat{P}=\hat{P}[/tex]
[tex]=0.41[/tex]
Now,
⇒ [tex]6 \hat{P}=\sqrt{\frac{\hat {P}(1-\hat{P})}{n} }[/tex]
[tex]=\sqrt{\frac{0.41\times 0.59}{524} }[/tex]
[tex]=0.0215[/tex]
[tex]P(\hat {P}>44 \ percent)[/tex]
or,
[tex]P(\hat{P}>0.44)[/tex]
[tex]=1-P(\hat{P}<0.44)[/tex]
[tex]=1-P(\frac{\hat{P}-\mu \hat{P}}{6 \hat{P}} <\frac{0.44-0.41}{0.0215} )[/tex]
[tex]=1-P(z<1.40)[/tex]
By using the standard normal table, we get
[tex]=1-0.9192[/tex]
[tex]=0.0808[/tex]
Questions 24-25. In 1963, postage was 5 cents per ounce. In 1981, postage was 18 cents per ounce.
If the trend had continued through to 2015, what would the postage per ounce be?
(round to the nearest central
The answer posted "42.55" is incorrect.
Answer:
The postage per ounce would be of $2.02.
Step-by-step explanation:
Exponential model:
The postage, in t years after 1963, follows the following format:
[tex]P(t) = P(0)(1+r)^t[/tex]
In which P(0) is the initial value and r is the growth rate, as a decimal.
In 1963, postage was 5 cents per ounce.
This means that [tex]P(0) = 5[/tex]
So
[tex]P(t) = P(0)(1+r)^t[/tex]
[tex]P(t) = 5(1+r)^t[/tex]
In 1981, postage was 18 cents per ounce.
This means that [tex]P(1981 - 1963) = P(18) = 18[/tex]. We use this to find r. So
[tex]P(t) = 5(1+r)^t[/tex]
[tex]18 = 5(1+r)^{18}[/tex]
[tex](1+r)^{18} = \frac{18}{5}[/tex]
[tex]\sqrt[18]{(1+r)^{18}} = \sqrt[18]{3.6}[/tex]
[tex]1 + r = (3.6)^{\frac{1}{18}}[/tex]
[tex]1 + r = 1.0738[/tex]
So
[tex]P(t) = 5(1.0738)^t[/tex]
If the trend had continued through to 2015, what would the postage per ounce be?
2015 - 1963 = 52, so this is P(52).
[tex]P(52) = 5(1.0738)^{52} = 202[/tex]
202 cents, so $2.02.
the percentage of people under the age of 18 was 23.5% in New York City, 25.8% in Chicago, and 26% in Los Angeles.
If one person is selected from each city, what is the probability that all of them are under 18?
Answer:
0.0158 = 1.58% probability that all of them are under 18.
Step-by-step explanation:
Probability of independent events:
If three events, A, B and C are independent, the probability of all happening is the multiplication of the probabilities of each happening, that is:
[tex]P(A \cap B \cap C) = P(A)P(B)P(C)[/tex]
The percentage of people under the age of 18 was 23.5% in New York City, 25.8% in Chicago, and 26% in Los Angeles.
This means that [tex]P(A) = 0.235, P(B) = 0.258, P(C) = 0.26[/tex]
If one person is selected from each city, what is the probability that all of them are under 18?
Since the three people are independent:
[tex]P(A \cap B \cap C) = 0.235*0.258*0.26 = 0.0158[/tex]
0.0158 = 1.58% probability that all of them are under 18.
A point is selected at random from a line segment of length l, dividing it into two line segments. What is the probability that the longer line segment is at least three times as long as the shorter segment
Answer:
3/4
Step-by-step explanation:
Let a be the length of the shorter line segment and b be the length of the longer line segment.
Since the length of the line segment is l, we have that the length of the line segment equals length of shorter line segment + length of longer line segment.
So, l = a + b
Since we require that the longer line segment be at least three times longer than the shorter line segment, we have that b = 3a
So, l = a + b
l = a + 3a
l = 4a
The probability that the shorter line segment will be a(or 3 times shorter than b) is P(a) = length of shorter line segment/length of line segment = a/l
Since l = 4a.
a/l = 1/4
So, P(a) = 1/4
The probability that a will be less than 3 times shorter that b is P(a ≤ 1) = P(0) + P(a) = 0 + 1/4 = 1/4
The probability that b will be 3 times or more greater than a is thus P(b ≥ 3) = 1 - P(a ≤ 1) = 1 - 1/4 = 3/4
A charter school did a local beach cleanup. They collected a total of 55 pounds of plastic bottles and aluminum cans. The California refund value for plastic is $1.60 per pound and $1.28 per pound for aluminum. The school recycled a total of $77.60 worth of plastic and aluminum. How many pounds of each, plastic and aluminum, did the class collect?
Answer:
Plastic is 22.5 pounds and aluminum is 32.5 pounds.
Step-by-step explanation:
total junk = 55 pounds
Value of plastic = $ 1.60 per pound
Value of aluminum = $ 1.28 per pound
Total value= $ 77.60
Let the plastic is p and the aluminum is 55 - p.
Total cost
77.60 = 1.6 p + (55 - p) x 1.28
77.60 = 1.6 p + 70.4 - 1.28 p
7.2 = 0.32 p
p = 22.5 pounds
So, plastic is 22.5 pounds and aluminum is 32.5 pounds.
Due to a sale at Macy's you only have to pay 2/3 of the original price of a blouse. your price AFTER the discount $120. What was the original price? Explain how you arrived at this answer.
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Answer:
$180
Step-by-step explanation:
The relationship between the prices is said to be ...
(amount you pay) = 2/3 × (original price)
To find the original price, multiply the equation by the reciprocal of the coefficient of the (original price).
(3/2)×(amount you pay) = (3/2)(2/3)(original price) = (original price)
(3/2)×$120 = original price = $180
Rewrite in simplest terms: (9x+5)-(-2x+10)(9x+5)−(−2x+10) . Someone please help me
Answer:
18x^(2)-69x-55
Step-by-step explanation:
dont have the time to rn
Answer:
[tex]{ \bf{(9x + 5) - ( - 2x + 10)(9x + 5) - ( - 2x + 10)}} \\ = { \tt{(9x + 5) - ( - {18x}^{2} + 80x + 50) - ( - 2x + 10)}} \\ = { \tt{(9 - 80 + 2)x + {18x}^{2} + 5 - 50 - 10 }} \\ = { \tt{ {18x}^{2} - 69x - 55}}[/tex]
Which statement is false?
A. Every irrational number is also real.
B. Every integer is also a rational number.
• C. Every rational number is also an integer.
D. No rational number is irrational.
Answer:
A. false B. true C. false D. true
Whope you all like this answer
The radius of a circle is 5 yd.
Answer the parts below. Make sure that you use the correct units in your answers.
If necessary, refer to the list of geometry formulas.
Answer:
Circumference =10 pi yard
Area =25 pi yard squared
Step-by-step explanation:
C=2*pi*r
Circumfrance =10 pi
A=pi r^2
Area =25 pi
For the estimate just sub in pi on the calculator for pi, then round to the hundreth.
Circumfrence= just the unit
Area= squared
Suppose that all of the points on the circular dartboard shown are equally likely to be hit by a dart. If the radius of the shaded center circle is 1 and the radius of the entire dartboard is 4, what is the probability of throwing a dart and hitting the white part of the board? Round your answer to the nearest whole number.
6%
34%
67%
94%
Answer:
94%
Step-by-step explanation:
Find the missing number?
Answer:
65 solve theprob
Step-by-step explanation:
sinolove ko po yan paki brainly
-2,6,-18,54, what is the common ratio of the sequence
Answer:
2
Step-by-step explanation:
Answer:
Common Ratio=-3
Step-by-step explanation:
To find any common ratio in a sequence, always take the second number in the sequence and divide it by the first number. However, you must be careful because the common ratio should only be negative if the values in the sequence are alternating between negative and positive. Therefore, if the sequence of numbers is simply decreasing in value, this does not mean that the common ratio is negative. The common ratio would still be positive. If the sequence is decreasing in value, this means that the common ratio would be a fraction or a decimal less than one.
The parametric equations for the paths of two projectiles are given. At what rate is the distance between the two objects changing at the given value of t? (Round your answer to two decimal places.) x1 = 10 cos(2t), y1 = 6 sin(2t) First object x2 = 4 cos(t), y2 = 4 sin(t) Second object t = π/2
Answer:
- [tex]\frac{4}{\sqrt{29} }[/tex]
Step-by-step explanation:
The equations for the 1st object :
x₁ = 10 cos(2t), and y₁ = 6 sin(2t)
2nd object :
x₂ = 4 cos(t), y₂ = 4 sin(t)
Determine rate at which distance between objects will continue to change
solution Attached below
Distance( D ) = [tex]\sqrt{(10cos2(t) - 4cos(t))^2 + (6sin2(t) -4sin(t))^2}[/tex]
hence; dD/dt = - [tex]\frac{4}{\sqrt{29} }[/tex]
The functions f (x) = 1/2x-3 and g(x) = -2x+ 2 intersect
at x = -2. True or false?
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Answer:
False
Step-by-step explanation:
f(-2) = (1/2)(-2) -3 = -1 -3 = -4
g(-2) = -2(-2) +2 = 4 +2 = 6
The function values are not the same at x=-2, so the graphs do not intersect there.
__
The graphs intersect at x=2.
six options. Each of these six options leads to a menu with four options. For each of these four options, three more options are available. For each of these three options, another three options are presented. If a person calls the 800 number for assistance, how many total options are possible
Answer:
Hence the total number of possible options available to a person who calls the 800 number is 216.
Step-by-step explanation:
Given that the caller 10 800 telephone system has six options. For each of these four options, three more options are available. For each of these three options, another three options are presented.
Hence the total number of possible options available to a person who calls the 800 number = [tex]6 \times 4 \times 3 \times 3 = 216[/tex].
Let P denote the set of primes and E the set of even integers. As always, Z and N denote the integers and natural numbers, respectively. Find equivalent formulations of each of the following statements using the notation of set theory
a. √2 is a real number but not a rational number.
b. Every integer is a rational number.
c. 2 is an even prime number.
Answer:
sorry i dont know this answer
Exactly how many planes contain points J, K, and N?
a - 0
b - 1
c - 2
d - 3
f(x) =x-4/x+5
and g(x) = 2x-1
Find the composition f•g
Step-by-step explanation:
2x-1 - (4/(2x-1)) + 5
2x^2 -4x -2 -4 + 10x - 5
2x^2 +6x -11
William invested $12,000 in a bank account that pays 9 percent simple interest. His friend invested the same amount at another bank that pays 8 percent interest compounded quarterly. These two functions, where t is time in years, represent the value of the investments: f(t) = 12(1.02)4t g(t) = 12(1.09)t The functions are graphed, and the point of intersection lies between 0.5 and 1.2. Based on the table, approximately how long will it be until both investments have the same value? Value of t f(t) = 12(1.02)4t g(t) = 12(1.09)t 0.5 12.48 6.54 0.6 12.58 7.84 0.7 12.68 9.16 0.8 12.79 10.46 0.9 12.89 11.87 1.0 12.99 13.08 1.1 13.09 14.39 1.2 13.20 15.70 A. 0.9 year B. 1.0 year C. 1.1 years D. 1.2 years
===========================================================
Explanation:
We have these two functions
f(t) = 12(1.02)^(4t)g(t) = 12(1.09)twhich represent the amounts for his friend and William in that order. Strangely your teacher mentions William first, but then swaps the order when listing the exponential function as the first. This might be slightly confusing.
The table of values is shown below. We have t represent the number of years and t starts at 0.5. It increments by 0.1
The f(t) and g(t) columns represent the outputs for those mentioned values of t. For example, if t = 0.5 years (aka 6 months) then f(t) = 12.48 and that indicates his friend has 12,480 dollars in the account.
I've added a fourth column labeled |f - g| which represents the absolute value of the difference of the f and g columns. If f = g, then f-g = 0. The goal is to see if we get 0 in this column or try to get as close as possible. This occurs when we get 0.09 when t = 1.0
So we don't exactly get f(t) and g(t) perfectly equal, but they get very close when t = 1.0
It turns out that the more accurate solution is roughly t = 0.9925 which is close enough. I used a graphing calculator to find this approximate solution.
It takes about a year for the two accounts to have the same approximate amount of money.
Answer:
B
Step-by-step explanation:
Gieo 120 hạt giống của một loại cây thấy có 15 hạt nảy mầm. Với độ tin cậy 95% hãy tìm ước lượng khoảng cho tỷ lệ nảy mầm của loại hạt giống đó.
Mn giúp mình với ạ
Answer:
sorry can't understand the language