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3 years ago

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The first and fifth terms of a geometric progression (G.P) are 2.5 and 40 respectively. If the common ratio is positive, find th

e sum of the first eight terms of the geometric progression

1 answer:

Nadusha1986 [10]3 years ago

5 0

Answer:

637.5

Step-by-step explanation:

$a_{1}=2.5=a\\a_{5}=40=ar^4\\r=2 \ \& \ a=2.5\\\text{Sum}=\frac{a(r^n-1)}{r-1}=\frac{2.5*(2^8-1)}{1}=637.5$

Love from Gauthmath.

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Suppose a large labor union wishes to estimate the mean number of hours per month a union member is absent from work. The union

frosja888 [35]

Answer:

The 99% confidence interval for the true mean number of hours a union member is absent per month is (0 hours, 16.5125 hours).

Step-by-step explanation:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1-0.99}{2} = 0.005$

Now, we have to find z in the Ztable as such z has a pvalue of $1-\alpha$ .

So it is z with a pvalue of $1-0.005 = 0.995$ , so $z = 2.575$

Now, find M as such

$M = z*s$

In which s is the standard deviation of the sample.

So

$M = 2.575*3.5 = 9.0125$

The lower end of the interval is the mean subtracted by M. So it is 7.5 - 9.0125 = -...

There is not a negative number of hours. So the lower end of the interval is 0 hours.

The upper end of the interval is the mean added to M. So it is 7.5 + 9.0125 = 16.5125 hours.

The 99% confidence interval for the true mean number of hours a union member is absent per month is (0 hours, 16.5125 hours).

8 0

3 years ago

Aubrey has a Shelf full of books exactly one third of books on the Shelf are Mysteries. Aubrey has read 10 of the mysteries on t

CaHeK987 [17]

The correct answer for this question is this one: "<span>147"</span>

Here's how to solve this problem.

Let <span>x = number of mystery books on the shelf </span>
<span>Let 3x = total number of books on the shelf </span>

<span>we are told that </span>
<span>x/5<10<x/4 </span>
<span>multiply by 20, </span>
<span>4x<200<5x </span>
<span>which means that </span>
<span>40<x<50 </span>
<span>So the number of mystery books can be any number between 41 and 49.
In other words, the possible total number of books could be three times the above numbers, 123, 126, 129,.... </span>
Choose the one that suits your answer choices.

Here are the following choices:
Which could be the number of books on the shelf?
A. 120 B 140 c 147 D 150

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3 years ago

Which of the graphs above represents a function?

mezya [45]

Answer: B

explanation: B is the right answer because it passes the vertical line test while the others do not. the others would have more than one outcome for the same income, therefore it wouldn’t be a function

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3 years ago

Ayúdaaaaaa si no me van a dar con la chancla

yKpoI14uk [10]

Answer:

1. 54 (muy bien!!!)

2. 270

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3 years ago

Help with 8th-grade middle school math show work

ss7ja [257]

Answer:

So for the triangle, we have x = 25 and the angles 45-75-60.

So for the quadrilateral, we have x = 75 and the angles 70-110-75-105.

Step-by-step explanation:

For each of these problems, we can simply add the expressions of the angles given matched to the sum of the angles for the shape given below. Once we do this, we can solve for x, and then state the given measures of each angle of the shapes.

<u>For the triangle:</u>

60 + ( x + 20 ) + 3x = 180

60 + x + 20 + 3x = 180

60 + 20 + x + 3x = 180

80 + x ( 1 + 3 ) = 180

80 + x ( 4 ) = 180

80 + 4x = 180

4x = 100

x = 25

We have the given angles:

x + 20 ==> 25 + 20 ==> 45

3x ==> 3 (25) ==> 75

60

So for the triangle, we have the angles 45-75-60.

<u>For the quadrilateral:</u>

( x - 5 ) + ( x + 35 ) + x + 1.4x = 360

x - 5 + x + 35 + x + 1.4x = 360

35 - 5 + x + x + x + 1.4x = 360

30 + x ( 1 + 1 + 1 + 1.4 ) = 360

30 + x ( 4.4 ) = 360

30 + 4.4x = 360

4.4x = 330

x = 75

So, we have the given angles:

x - 5 ==> 75 - 5 ==> 70

x + 35 ==> 75 + 35 ==> 110

x ==> 75

1.4x ==> 1.4(75) ==> 105

So for the quadrilateral, we have the angles 70-110-75-105.

Cheers.

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3 years ago

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