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3 years ago

8

There are 20 donuts in 4 boxes. How many donuts are in each box?

1 answer:

Serga [27]3 years ago

3 0

Answer:

5

Step-by-step explanation

20 divided by 4 equals 5

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Salsk061 [2.6K]

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3 years ago

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Is there any way for my to view my full highschool transcript online

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3 years ago

The first 4 terms of a 10-term geometric series are listed below. Which expression represents the sum

Stella [2.4K]

Given:

First 10 term of a geometric series are:

$\dfrac{16}{25}+\dfrac{8}{5}+4+10+...+a_10$

To find:

The expression that represents the sum of the series.

Solution:

The first term of the given geometric series is:

$a_1=\dfrac{16}{25}$

The common ratio of the given geometric series is:

$r=\dfrac{a_2}{a_1}$

$r=\dfrac{\dfrac{8}{5}}{\dfrac{16}{25}}$

$r=\dfrac{8}{5}\times \dfrac{25}{16}$

$r=\dfrac{5}{2}$

The sum of first n terms of a geometric sequence is:

$S_n=\dfrac{a_1(1-r^n}{1-r}$

Where r is the common ratio.

Putting $a_1=\dfrac{16}{25},r=\dfrac{5}{2},n=10$ in the above formula, we get

$S_{10}=\dfrac{16}{25}\left(\dfrac{(1-(\dfrac{5}{2})^{10}}{1-\dfrac{5}{2}}\right)$

Therefore, the correct option is C, i.e., $\dfrac{16}{25}\left(\dfrac{(1-(\dfrac{5}{2})^{10}}{1-\dfrac{5}{2}}\right)$ .

5 0

3 years ago

Keenan has 35 CDs and 55 DVDs. What is the ratio of DVDs to CDs?

Sav [38]

The ration is 10/7

Divide 55 and 35 by 5 to reduce the fraction of 55/35 and you get 10/7

8 0

3 years ago

Read 2 more answers

A new post-surgical treatment is being compared with a standard treatment. Seven subjects receive the new treatment, while seven

a_sh-v [17]

Answer:

$(17.714-28.714) -2.681 \sqrt{\frac{4.461^2}{7} +\frac{7.387^2}{7}}= -19.745$

$(17.714-28.714) +2.681 \sqrt{\frac{4.461^2}{7} +\frac{7.387^2}{7}}= -2.255$

Step-by-step explanation:

For this case we have the following info given:

Treatment: 12 13 15 19 20 21 24

Control: 18 23 24 30 32 35 39

We can find the sample mean and deviations with the the following formulas:

$\bar X = \frac{\sum_{i=1}^n X_i}{n}$

$s =\sqrt{\frac{\sum_{i=1}^n (X_i- \bar X)^2}{n-1}}$

And repaplacing we got:

$\bar X_T = 17.714$ the sample mean for treatment

$\bar X_C = 28.714$ the sample mean for treatment

$s_T= 4.461$ the sample deviation for treatment

$s_C= 7.387$ the sample deviation for control

$n_T= n_C= 7$ the sample size for each sample

The degrees of freedom are given by:

$df= 7+7-2= 12$

The confidence interval for the difference of means is given by:

$(\bar X_T -\bar X_C) \pm t_{\alpha/2} \sqrt{\frac{s^2_T}{n_T} +\frac{s^2_C}{n_C}}$

The confidence is 98% so then the significance is $\alpha=0.02$ and $\alpha/2 =0.01$ . Then the critical value would be:

$t_{\alpha/2}=2.681$

And replacing we got:

$(17.714-28.714) -2.681 \sqrt{\frac{4.461^2}{7} +\frac{7.387^2}{7}}= -19.745$

$(17.714-28.714) +2.681 \sqrt{\frac{4.461^2}{7} +\frac{7.387^2}{7}}= -2.255$

4 0

4 years ago