Find the third term of a geometric progression if the sum of the first three terms is equal to 12, and the sum of the first six terms is equal to (−84).
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.
X^2-y^2=k need the answer
Answer:
Let's solve for k.
x2−y2=k
Step 1: Flip the equation.
k=x2−y2
Answer:
k=x2−y2
Step-by-step explanation:
Negate this conditional statement. Please show proper work and an explanation. Those who attempt to just respond in order to get a lot of points shall be reported. Thank you.
Answer:
a AND ~c
Step-by-step explanation:
you can find the full explanation in wikipedia:
https://en.m.wikipedia.org/wiki/Material_conditional
under "Negated conditionals"
The number of runners in the London Marathon on 25th April, 2010 was 37 527.
Work out an estimate for the number of these runners whose birthday was on that day.
Answer:
Hi 34
Step-by-step explanation:
Hi
Not sure I would solve this problem or where to start? Can someone help me out here please?
Answer:
$2419469.58
Step-by-step explanation:
You are given the original player salary and told that there is a pay decrease of 2.7%.
So New Salary= Original Salary-Pay Decrease.
If original is 100% and pay decrease is 2.7% then the new salary is 97.3% of original.
New Salary= 0.973*2486609=$2419469.58
Whoever helps me with this question I will give them brainliest
Hi there I hope you are having a great day :) I am pretty sure that you do 280 degrees around angle so i would say you would add 63 + 73 + 83 = 219 then you would take away it 280 - 219 = 61 so y must equal to 61 this is because we can see a z shape and a z shape adds up to 280.
Hopefully that helps you.
The time for a professor to grade a student’s homework in statistics is normally distributed with a mean of 13.3 minutes and a standard deviation of 2.0 minutes. What is the probability that randomly selected homework will require less than 17 minutes to grade?
Answer:
0.96784
Step-by-step explanation:
17-13.3/2
=1.85
p(x<1.85)
=0.96784
The probability that randomly selected homework will require less than 17 minutes to grade is 0.9678.
Mean [tex]\mu[/tex]=13.3 minutes
Standard deviation[tex]\sigma[/tex]=2 minutes
What is a z-score?The value of the z-score tells you how many standard deviations you are away from the mean.
So, the z-score of the above data
[tex]z=\frac{x-\mu}{\sigma}[/tex]
[tex]z=\frac{17-13.3}{2}[/tex]
[tex]z=1.85[/tex]
From the standard normal table, the p-value corresponding to z=1.85
Or, p(x<1.85)=0.9678 or 96.78%
Hence, the probability that randomly selected homework will require less than 17 minutes to grade is 0.9678.
To get more about the z-score visit:
https://brainly.com/question/25638875
The function y=5(1/2)^x Models the number of grams of radioactive material, y, left in a container after x days. Sketch the graph of this function below
Answer:
see graph
Step-by-step explanation:
What can you say about the y-values of the two functions f(x) = 3x -3 and
g(x) = 7x2 -3?
9514 1404 393
Answer:
the y-values of g(x) are limited to values of at least -3, those of f(x) are not limitedthe y-values are the same for two different x-valuesStep-by-step explanation:
You can say lots of things about the y-values of these functions. A couple of observations are listed above. In addition, we can say the y-values of g(x) will be greater than those of f(x) for x-values not equal or between the x-values where the y-values are the same.
Answer:
• g(x) has the smallest possible y-value.
• The minimum y value of g(x) is -3.
Step-by-step explanation:
Ap3x
Please select the best answer from the choices provided
A
B
C
D
Answer:
C
Step-by-step explanation:
Answer: B
Step-by-step explanation:
Calculate the difference and enter it below
-6 - 12
Answer:
-18
Step-by-step explanation:
Answer: -18 is the difference
Step-by-step explanation:
Evaluate = -18
Find the value of y .
Please help !
9514 1404 393
Answer:
(b) √55
Step-by-step explanation:
The right triangles in this geometry are all similar, so the ratio of long side to short side is the same:
y/5 = 11/y
y² = 55 . . . . . . multiply by 5y
y = √55 . . . . . take the square root
__
And x=4√5 by looking at ratios of short side to hypotenuse.
Find the mean or average of these savings accounts $215, $156,$318, $75, and $25
Answer:
157.8
Step-by-step explanation:
Add them all up to get 789 and divide them by 5 as there are five numbers to get the answer:)
A simple random sample of students could be achieved by stopping every other student who enters the library.
a. True
b. False
Find the probability that when a couple has children, at least one of them is a . (Assume that boys and girls are equally likely.)
Answer:
[tex]P(At\ least\ one\ girl) = 0.875[/tex]
Step-by-step explanation:
Given
[tex]n = 3[/tex]
[tex]B \to boys[/tex]
[tex]G \to girls[/tex]
[tex]P(G) = P(B) = 0.5[/tex] --- equal probability
See comment for complete question
Required:
[tex]P(At\ least\ one\ girl)[/tex]
To do this, we make use of complement rule:
[tex]P(At\ least\ one\ girl) = 1 - P(No\ girl)[/tex]
The event that there is no girl out of the 3 children is: B B B
And the probability is:
[tex]P(No\ Girl) = P(B) * P(B) * P(B)[/tex]
[tex]P(No\ Girl) = 0.5*0.5*0.5[/tex]
[tex]P(No\ Girl) = 0.125[/tex]
So:
[tex]P(At\ least\ one\ girl) = 1 - P(No\ girl)[/tex]
[tex]P(At\ least\ one\ girl) = 1 - 0.125[/tex]
[tex]P(At\ least\ one\ girl) = 0.875[/tex]
Your friend is looking at laptops for college, and is comparing the different
screen sizes. Use the diagram and formula below to find the height of the
laptop screen. Round your answer to the tenths place.
d - VW
d= 72.7mn
h
W 026
Answer:
B. h = 7.4 inches
Step-by-step explanation:
height of the laptop screen = h
d = 12.1 in.
w = 9.6 in.
We are given the formula,
d = √(w² + h²)
Plug in the values and solve for h
12.1 = √(9.6² + h²)
Square both sides
12.1² = 9.6² + h²
146.41 = 92.16 + h²
146.41 - 92.16 = h²
54.25 = h²
√54.25 = h
7.4 = h (nearest tenth)
h = 7.4 inches
A
(8x - 5) in.
B
The perimeter of parallelogram ABCD is 46 inches.
What is DA?
03 in
O 4 in
8 in.
O 19 in
D
С
(3x + 10) in
[Not drawn to scale]
Lisa, an experienced shipping clerk, can fill a certain order in 9 hours. Felipe, a new clerk, needs 10 hours to do the same job. Working together, how long will it take them to fill the order?
Answer:
9.5hrs
Step-by-step explanation:
since they are working together you have to take the average time since is the same order
There are 4 white and 5 red (indistinguishable) balls in a bag. Suppose you draw one ballout at a time without replacement and stop when you have drawn all the white (4 white) orall the red (5 red) balls. What is the probability that the last ball you drawn was a whiteball?
Answer:
5/9
Step-by-step explanation:
What we have in this question are four white balls and 5 red balls.
This is the sample space
[(4w,0R) (4w,1R)(4w,2R)(4w,3R)(4w,4R)(0w,5R)(1w,5R)(2w,5R)
So we have 9 possible sets of events
The event number with the last ball being white = 5
Probability of the last ball drawn being white = 5/9
= 0.56
Please help me i will give brainlest please i need help
Answer:
Since you didn't mention which question.
Step-by-step explanation:
13.
[tex]1.\overline{52}\\[/tex] = 1.525252...
Let x = 1.525252...
10x = 15.2525252....
100x = 152.525252...
100x - x = 151.00
99x = 151
[tex]x = \frac{151}{99}\\\\or\\\\x = 1 \frac{52}{99}[/tex]
14.
4x + 10 = 8x - 26 [ corresponding angles are congruent ]
4x - 8x = - 26 - 10
- 4x = - 36
[tex]x = \frac{-36}{-4} \\\\x = 9[/tex]
15.
Given breadth of a rectangle is ( 2/3) its length.
Let the length be x
Therefore, breadth = ( 2 /3) of x
[tex]= \frac{2}{3} \times x\\\\=\frac{2}{3}x[/tex]
Given perimeter = 40m
Perimeter of a rectangle = 2( length + breadth)
[tex]40 = 2 (x + \frac{2}{3}x )\\\\\frac{40}{2} = \frac{2}{2}(x + \frac{2}{3}x)\\\\20 = x + \frac{2}{3}x\\\\20 = \frac{3x + 2x}{3}\\\\20 \times 3 = 5x \\\\x = \frac{60}{5}\\\\x = 12\\\\Therefore, Length = x = 12 \ m \ and \ breadth = \frac{2}{3}x = \frac{2}{3} \times 12 = 8 \ m[/tex]
16.
Sum of the angles of a triangle = 180°
Given ratio = 2 : 3 : 4
Sum of the ratio = 9
Therefore,
[tex]first \ angle = \frac{2}{9} \times 180 = 2 \times 20 = 40 ^\circ\\\\Second \ angle = \frac{3}{9} \times 180 = 3 \times 20 = 60^\circ\\\\Third angle = \frac{4}{9} \times 180 = 4 \times 20 = 80^\circ[/tex]
17.
Sum of interior angles of a polygon with n sides = ( n - 2) x 180°
Given polygon is pentagon, that is n = 5
Therefore, sum of the interior angles = ( 5 - 2) x 180 = 3 x 180 = 540°
That is ,
x + 125 + 125 + 88 + 60 = 540°
x + 398 = 540°
x = 540 - 398
x = 142°
Answer:
Please can you say which question?
Thank you
1. Suppose half of all newborns are girls and half are boys. Hospital A, a large city hospital, records an average of 50 births a day. Hospital B, a small, rural hospital, records an average of 10 births a day. On a particular day, which hospital is less likely to record 80% or more female births?
Answer:
5%
Step-by-step explanation:
Hospital A (with 50 births a day), because the more births you see, the closer the proportions will be to 0.5.
Hospital B (with 10 births a day), because with fewer births there will be less variability.
The two hospitals are equally likely to record such an event, because the probability of a boy does not depend on the number of births
Two hospitals have an equal chance of recording such an event.
What is probability?The area of mathematics known as probability deals with numerical representations of the likelihood that an event will occur or that a statement is true. An event's probability is a number between 0 and 1, where, roughly speaking, 0 denotes the event's impossibility and 1 denotes certainty.
Given
Hospital A (with 50 births per day), as the proportions will be closer to 0.5 the more births you see.
Hospital B (with 10 births per day), thus there will be less unpredictability with fewer births.
Due to the fact that the likelihood of a boy does not rely on the number of births, the two hospitals have an equal chance of recording such an event.
To learn more about probability refer to:
https://brainly.com/question/13604758
#SPJ2
what is the best deal for diet coke?
12oz. for $.99
64oz. for $.2.99
128oz. for $4.99
Answer:
128 for 4.99
64 for 2.99 times 2 is more than 4.99.
12 oz. for 0.99 is also more than 4.99.
Which of the following values cannot be probabilities? 3/5, 2, 0, 1, −0.45, 1.44, 0.05, 5/3 Select all the values that cannot be probabilities.
Given:
The numbers are [tex]\dfrac{3}{5},2,0,1,-0.45, 1.44[/tex].
To find:
All the values that cannot be probabilities.
Solution:
We know that,
[tex]\text{Probability}=\dfrac{\text{Favorable outcomes}}{\text{Total outcomes}}[/tex]
The minimum value of favorable outcomes is 0 and the maximum value is equal to the total outcomes. So, the value of probability lies between 0 and 1, inclusive. It other words, the probability lies in the interval [0,1].
[tex]0\leq \text{Probability}\leq 1[/tex]
From the given values only [tex]\dfrac{3}{5}, 0, 1[/tex] lie in the interval [0,1]. So, these values can be probabilities.
The values [tex]2,-0.45, 1.44[/tex] does not lie in the interval [0,1]. So, these values cannot be probabilities.
Therefore, the correct values are [tex]2,-0.45, 1.44[/tex].
oludonts c) 2x + y = 2
2x + 2y = 0
Answer:
[tex]x = 2[/tex]
[tex]y = -2[/tex]
Step-by-step explanation:
Given
[tex]2x + y = 2[/tex]
[tex]2x + 2y = 0[/tex]
Required
Solfe for x and y
Subtract both equations
[tex]2x- 2x + y - 2y = 2 -0[/tex]
[tex]-y = 2[/tex]
Divide by -1
[tex]y = -2[/tex]
Substitute [tex]y = -2[/tex] in [tex]2x + 2y = 0[/tex]
[tex]2x+2 *-2 = 0[/tex]
[tex]2x-4 = 0[/tex]
[tex]x - 2 = 0[/tex]
Collect like terms
[tex]x = 2[/tex]
Solve the inequality. |X-15|>9
Answer:
X<6 or X>24
Step-by-step explanation:
Find the intersection of the parabola y=x^2+4x+3 and the line x-y=-1
Answer:
1
Step-by-step explanation:
Which value of n makes the equation true?
-1/2n=-8
Answer:
16?
Step-by-step explanation:
I'm not sure. I hope so.
What is division story problem where the dividend is a three-digit number and the divisor is a single digit.
Answer:
dddddddddv
Step-by-step explanation:
Please help ASAP !!! Thank you !
If $6,000 is invested in a bank account at an interest rate of 9 per cent per year, find the amount in the bank after 5 years if interest is compounded annually, quarterly, monthly, and continuously.
Answer:
annual - $9,231.74
quarterly - $9,363.06
monthly - $9,394.09
continuously -$9,409.87
Step-by-step explanation: