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Yakvenalex [24]
3 years ago
11

A biology teacher has 15 milliliters of a salt solution that is 65% salt. How many milliliters of water must the teacher add to

make a solution that is 25% salt?
Mathematics
1 answer:
My name is Ann [436]3 years ago
7 0
Assuming that water has 0% salt and that the amount of water added is x ml;

(15+x)*25 = (15+0)*65 = 975
375+25x = 975
25x = 975-375 = 600
x = 600/25 = 24 ml

The teacher must add 24 ml of water.
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Claudia studied for 45 minutes. Crystal studied for 5 minutes.
andreev551 [17]

Answer:

The number of minutes Claudia studied is <u>9</u> times as many minutes that Crystal studied.

Step-by-step explanation:

45/5=9

8 0
2 years ago
What is the image of this figure after this sequence of dilations?
frutty [35]

Answer:

Gshafaufqyffqyfwuauwuwuwuwiwiqiqiyehsi

3 0
2 years ago
Please help me almost done
Gnom [1K]

Answer:

x = -8

<XCE = 30

Step-by-step explanation:

Remark

In any question like this, there are 8 possible answers. Of the 8, 4 are acute angles and 4 are obtuse. So any pair are either equal to each other, or they are supplementary. In this case the two given angles are equal.

We have a little bit of both in this question.

Solution

3x + 174 = - 7x + 94                  Alternate exterior angles. Add 7x to both sides.

3x+7x +174 = 94                       Combine

10x + 174 = 94                          Subtract 174 from both sides

10x = 94 - 174

10x = - 80                                 Divide by 10

x = - 80/10

x = - 8

===================

Check

3x + 174 = -24 + 174 = 150

-7x + 94 = -7*-8 + 94

-7x + 94 = 56 + 94 = 150

<XCE

<XCE = 180 - (3x + 174)

<XCE = 180 - (-24 + 174)

<XCE = 180 - (150)

<XCE = 30

3 0
3 years ago
A recent study focused on the number of times men and women who live alone buy take-out dinner in a month. Assume that the distr
Marianna [84]

Answer:

(a) Decision rule for 0.01 significance level is that we will reject our null hypothesis if the test statistics does not lie between t = -2.651 and t = 2.651.

(b) The value of t test statistics is 1.890.

(c) We conclude that there is no difference in the mean number of times men and women order take-out dinners in a month.

(d) P-value of the test statistics is 0.0662.

Step-by-step explanation:

We are given that a recent study focused on the number of times men and women who live alone buy take-out dinner in a month.

Also, following information is given below;

Statistic : Men      Women

The sample mean : 24.51      22.69

Sample standard deviation : 4.48    3.86

Sample size : 35    40

<em>Let </em>\mu_1<em> = mean number of times men order take-out dinners in a month.</em>

<em />\mu_2<em> = mean number of times women order take-out dinners in a month</em>

(a) So, Null Hypothesis, H_0 : \mu_1-\mu_2 = 0     {means that there is no difference in the mean number of times men and women order take-out dinners in a month}

Alternate Hypothesis, H_A : \mu_1-\mu_2\neq 0     {means that there is difference in the mean number of times men and women order take-out dinners in a month}

The test statistics that would be used here <u>Two-sample t test statistics</u> as we don't know about the population standard deviation;

                      T.S. =  \frac{(\bar X_1-\bar X_2)-(\mu_1-\mu_2)}{s_p \sqrt{\frac{1}{n_1}+\frac{1}{n_2}  } }  ~ t__n_1_-_n_2_-_2

where, \bar X_1 = sample mean for men = 24.51

\bar X_2 = sample mean for women = 22.69

s_1 = sample standard deviation for men = 4.48

s_2 = sample standard deviation for women = 3.86

n_1 = sample of men = 35

n_2 = sample of women = 40

Also,  s_p=\sqrt{\frac{(n_1-1)s_1^{2}+(n_2-1)s_2^{2}  }{n_1+n_2-2} }  =  \sqrt{\frac{(35-1)\times 4.48^{2}+(40-1)\times 3.86^{2}  }{35+40-2} } = 4.16

So, <u>test statistics</u>  =  \frac{(24.51-22.69)-(0)}{4.16 \sqrt{\frac{1}{35}+\frac{1}{40}  } }  ~ t_7_3

                              =  1.890

(b) The value of t test statistics is 1.890.

(c) Now, at 0.01 significance level the t table gives critical values of -2.651 and 2.651 at 73 degree of freedom for two-tailed test.

Since our test statistics lies within the range of critical values of t, so we have insufficient evidence to reject our null hypothesis as it will not fall in the rejection region due to which <u>we fail to reject our null hypothesis</u>.

Therefore, we conclude that there is no difference in the mean number of times men and women order take-out dinners in a month.

(d) Now, the P-value of the test statistics is given by;

                     P-value = P( t_7_3 > 1.89) = 0.0331

So, P-value for two tailed test is = 2 \times 0.0331 = <u>0.0662</u>

4 0
3 years ago
Find the area of an equilateral triangle with apothem 7 cm.
lbvjy [14]
So hmm check the picture below

using the 30-60-90 rule, we get that much.. .bear in mind, an equilateral triangle has all equal sides, and therefore, all equal angles, so each angle is 60°, run a median through it from the center, and you split it in half

\bf \textit{area of an equilateral triangle}\\\\&#10;A=\cfrac{s^2\sqrt{3}}{4}\qquad &#10;\begin{cases}&#10;s=\textit{length of one side}\\&#10;----------\\&#10;s=14\sqrt{3}&#10;\end{cases}\implies A=\cfrac{(14\sqrt{3})^2\sqrt{3}}{4}&#10;\\\\\\&#10;A=\cfrac{14^2\cdot 3\sqrt{3}}{4}\implies A=\cfrac{588\sqrt{3}}{4}\implies A=147\sqrt{3}

8 0
3 years ago
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