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n200080 [17]
2 years ago
15

What is the sum of the first 9 terms of 7+21+63+...

Mathematics
1 answer:
attashe74 [19]2 years ago
7 0

Answer:

Step-by-step explanation:

7

21

+63 =91

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The expression 2(l + w) is used to calculate the perimeter of a rectangle, where l is length and w is width. If the length is 2/
xeze [42]

Answer:

P = 10/7 units

Step-by-step explanation:

Answer:

w ≥ 6

l ≥ 11

Step-by-step explanation:

The perimeter of a rectangle is equal to P = 2(l+w) where l=length and w=width. Here the length is 2/7. This means the width is 3/7. Substitute l=2/7 and w=3/7 into the perimeter equation. Then solve for P.

P = 2(\frac{2}{7} +\frac{3}{7} )\\\\P = 2(\frac{5}{7})\\\\P = \frac{10}{7}

6 0
3 years ago
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A​ half-century ago, the mean height of women in a particular country in their 20s was 64.7 inches. Assume that the heights of​
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Answer:

99.5% of all samples of 21 of​ today's women in their 20's have mean heights of at least 65.86 ​inches.

Step-by-step explanation:

We are given that a half-century ago, the mean height of women in a particular country in their 20's was 64.7 inches. Assume that the heights of​ today's women in their 20's are approximately normally distributed with a standard deviation of 2.07 inches.

Also, a samples of 21 of​ today's women in their 20's have been taken.

<u><em /></u>

<u><em>Let </em></u>\bar X<u><em> = sample mean heights</em></u>

The z-score probability distribution for sample mean is given by;

                          Z = \frac{\bar X -\mu}{\frac{\sigma}{\sqrt{n} } } ~ N(0,1)

where, \mu = population mean height of women = 64.7 inches

            \sigma = standard deviation = 2.07 inches

The Z-score measures how many standard deviations the measure is away from the mean. After finding the Z-score, we look at the z-score table and find the p-value (area) 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.

Now, Probability that the sample of 21 of​ today's women in their 20's have mean heights of at least 65.86 ​inches is given by = P(\bar X \geq 65.86 inches)

  P(\bar X \geq 65.86 inches) = P( \frac{\bar X -\mu}{\frac{\sigma}{\sqrt{n} } } \geq \frac{65.86-64.7}{\frac{2.07}{\sqrt{21} } } ) = P(Z \geq -2.57) = P(Z \leq 2.57)

                                                                        = <u>0.99492  or  99.5%</u>

<em>The above probability is calculated by looking at the value of x = 2.57 in the z table which has an area of 0.99492.</em>

<em />

Therefore, 99.5% of all samples of 21 of​ today's women in their 20's have mean heights of at least 65.86 ​inches.

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3 years ago
Term of the arithmetic sequence 12, 10, 8
r-ruslan [8.4K]

Answer:

\mathtt{\huge\star{\pink{\underline{ 12,\: 10,\: 8,\: 6,\:4,\:2,\:-1,/:-3........ infinite      }}}}\huge\star

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2 years ago
How to find n in 38n4​
Rus_ich [418]

Answer:

Step-by-step explanation:

imagine 38 n = lets say b

so b/b/b/b/b

and divide that by 38

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2 years ago
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juin [17]

Answer:

Answer to 9 is B answer to 10 is C

Step-by-step explanation:

Please give brainliest

7 0
3 years ago
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