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3 years ago

What is the sum of the first ten terms of the sequence -82,-76,-70,-64?

1 answer:

3 0

To find the sum of a geometri sequence from first term to nth term you do
Sn=(n(a1+an))/2

a1=-82
n=10

hmm
common difference is 6 since adding 6 each time
first term is -82
10th term is -82+6(10-1)=-28

sum of 10 terms is

Sn=(10(-82-28))/2
Sn=(10(-110))/2
Sn=(-1100)/2
Sn=-550

answer is -550

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7x - 7 = 126 what is x

Evgen [1.6K]

Answer:

Step-by-step explanation:

7x-7=126

add+7 to 126 and you will get 133

7x/133

x=19

6 0

3 years ago

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A sample has a mean of M = 90 and a standard devia-tion of s 20.=a. Find the z-score for each of the following X values.X = 95X

sladkih [1.3K]

Answer:

$\begin{gathered} X=95,z=0.25 \\ X=80,z=-0.5 \\ X=98,z=0.4 \\ X=88,z=-0.1 \\ X=105,z=0.75 \\ X=76,z=-0.7 \end{gathered}$

Explanation:

Given a sample with the following:

• Mean,M = 90

• Standard deviation, s = 20

To find the z-score for each of the given X values, we use the formula below:

$\begin{equation*} z-score=\frac{X-\mu}{\sigma}\text{ where }\begin{cases}{X=Raw\;Score} \\ {\mu=mean} \\ {\sigma=Standard\;Deviation}\end{cases} \end{equation*}$

The z-scores are calculated below:

$\begin{gathered} \text{When X=95, }z=\frac{95-90}{20}=\frac{5}{20}=0.25 \\ \text{When X=80, }z=\frac{80-90}{20}=\frac{-10}{20}=-0.5 \\ \text{When X=98, }z=\frac{98-90}{20}=\frac{8}{20}=0.4 \end{gathered}$ $\begin{gathered} \text{When X=88,}z=\frac{88-90}{20}=\frac{-2}{20}=-0.1 \\ \text{When X=105, }z=\frac{105-90}{20}=\frac{15}{20}=0.75 \\ \text{When X=76, }z=\frac{76-90}{20}=\frac{-14}{20}=-0.7 \end{gathered}$

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1 year ago

The surface areas of two similar figures are 25 in2 and 36 in2. If the volume of the smaller figure is 250 in3, what is the volu

Slav-nsk [51]

Since the figures are similar, we can establish a rule of three as follows.
We know that the area of the smaller figure is $25in^{2}$ , and its volume is $250in^{3}$ . We also know that the area of the larger figure is $36in^{2}$ ; since we don't now its volume, lets represent it with $X$ :
$\frac{25in^{2}----\ \textgreater \ 250in^{3}}{36in^{2}----\ \textgreater \ Xin^{3}}$
$\frac{25}{36} = \frac{250}{X}$
$X= \frac{(250)(36)}{25}$
$X=360$

We can conclude that the volume of the larger figure is $360in^{3}$ ; therefore, the correct answer is a.

6 0

3 years ago

Read 2 more answers

You pay sales tax on your purchases at the rate of 0.07. What fraction of your money is this? Remember to reduce your fraction

Gemiola [76]

Answer:

This is $\frac{7}{100}$ of your money.

Step-by-step explanation:

We have a decimal number, and we want the answer to be a fraction. To transform a decimal number into a fraction, we multiply both the numerator and the denominator by 10 until none of them have decimal parts. So

$0.07\times \frac{10}{10} = \frac{0.7}{10}\times \frac{10}{10} = \frac{7}{100}$

This is $\frac{7}{100}$ of your money.

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3 years ago

Write “400 pounds per 340 square feet” as a rate in simplest form

quester [9]

I think its 20 pounds per 17 square feet (simplest form)

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3 years ago