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3 years ago

How much water must be added to 5 qt of a saline solution that is 20% salt in order to reduce it to 15% salt?

Mathematics

1 answer:

jeka943 years ago

7 0

Answer:

your answer is 40

Step-by-step explanation:

5+20+15=

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In the past decades there have been intensive antismoking campaigns sponsored by both federal and private agencies. In one study

astra-53 [7]

Answer:

C. z = 2.05

Step-by-step explanation:

We have to calculate the test statistic for a test for the diference between proportions.

The sample 1 (year 1995), of size n1=4276 has a proportion of p1=0.384.

$p_1=X_1/n_1=1642/4276=0.384$

The sample 2 (year 2010), of size n2=3908 has a proportion of p2=0.3621.

$p_2=X_2/n_2=1415/3908=0.3621$

The difference between proportions is (p1-p2)=0.0219.

$p_d=p_1-p_2=0.384-0.3621=0.0219$

The pooled proportion, needed to calculate the standard error, is:

$p=\dfrac{X_1+X_2}{n_1+n_2}=\dfrac{1642+1415}{4276+3908}=\dfrac{3057}{8184}=0.3735$

The estimated standard error of the difference between means is computed using the formula:

$s_{p1-p2}=\sqrt{\dfrac{p(1-p)}{n_1}+\dfrac{p(1-p)}{n_2}}=\sqrt{\dfrac{0.3735*0.6265}{4276}+\dfrac{0.3735*0.6265}{3908}}\\\\\\s_{p1-p2}=\sqrt{0.00005+0.00006}=\sqrt{0.00011}=0.0107$

Then, we can calculate the z-statistic as:

$z=\dfrac{p_d-(\pi_1-\pi_2)}{s_{p1-p2}}=\dfrac{0.0219-0}{0.0107}=\dfrac{0.0219}{0.0107}=2.05$

z=2.05

4 0

3 years ago

Find the equation of the line that contains the given point and is parallel to the given line. Write the equation in slope-inter

AlexFokin [52]

Answer:

Step-by-step explanation:

5 0

3 years ago

What is the y-coordinate of the point that divides the directed

e-lub [12.9K]

Answer:

(D)5

Step-by-step explanation:

Given the point J(-3,1) and K(8,11).

The line segment that divides the segment from J to K in any given ratio can be determined using the formula.

$P(x,y)=\left(\dfrac{mx_2+nx_1}{m+n} ,\dfrac{my_2+ny_1}{m+n}\right)$

In the given case:

$(x_1,y_1)=(-3,1), (x_2,y_2)=(8,11)$ , m:n=2:3

Since we are to determine the y-coordinate of the point that divides JK into a ratio of 2:3, we have:

$\dfrac{my_2+ny_1}{m+n}=\dfrac{2*11+3*1}{3+2}\\\\=\dfrac{22+3}{5}\\\\=\dfrac{25}{5}\\\\=5$

The y-coordinate of the point that divides the directed line segment from J to K into a ratio of 2:3 is 5.

The correct option is D.

3 0

3 years ago

Solve the system by adding or subtracting x - 2y = - 13 5 x + 2y = -17

Delvig [45]

You subtract and find x=10

5 0

4 years ago

Read 2 more answers

Complete the following statement. 3(4 x 8) (3 x4) (_)

shutvik [7]

Answer:

Step-by-step explanation:

(8*4)3=96

3*4=12

12*8=96

8 0

3 years ago