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3 years ago

How to do this question plz answer me

Mathematics

1 answer:

Sati [7]3 years ago

7 0

Answer:

$d = \frac{4 - 3c}{c + 1}$

Step-by-step explanation:

To make d the subject of formula, we need to rearrange the equation such that we arrive at d= _____.

$c = \frac{4 - d}{d + 3}$

Remove the fraction by multiplying (d +3) on both sides:

$c(d + 3) = 4 - d$

Expand:

$cd + 3c = 4 - d$

Bring all the d terms to one side and move the others to the other side of the equation:

$cd + d = 4 - 3c$

Factorise d out:

$d(c + 1) = 4 - 3c$

Divide by (c +1) on both sides:

$d = \frac{4 - 3c}{c + 1}$

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A person recently read that 84% of cat owners are women. How large a sample should the researcher take if she wishes to be 90% c

Lana71 [14]

Answer:

405

Step-by-step explanation:

To find sample size, use the following equation, where n = sample size, za/2 = the critical value, p = probability of success, q = probability of failure, and E = margin of error.

$n=\frac{(z_{\frac{\alpha }{2} })^{2} *p*q }{E^2}$

The values that are given are p = 0.84 and E = 0.03.

You can solve for the critical value which is equal to the z-score of (1 - confidence level)/2. Use the calculator function of invNorm to find the z-score. The value will given with a negative sign, but you can ignore that.

(1 - 0.9) = 0.1/2 = 0.05

invNorm(0.05, 0, 1) = 1.645

You can also solve for q which is 1 - p. For this problem q = 1 - 0.84 = 0.16

Plug the values into the equation and solve for n.

$n =\frac{(1.645)^2*0.84*0.16}{(0.03)^2}\\n= 404.0997333$

Round up to the next number, giving you 405.

6 0

3 years ago

Two trains leave the station at the same time, one heading east and the other west. The eastbound train travels 16 miles per hou

Verizon [17]

We'll use variables to represent the speeds of the eastbound and westbound trains.

x will represent the speed of the eastbound train.
y will represent the speed of the westbound train.

The eastbound train is 16 mph faster than the westbound train. An equation can be made from this:

$x - y = 16$

Subtraction is used, because it represents the difference in distances between the two trains if they travel the same direction.

After 4 hours, the trains are 800 miles apart. An equation can be made from this:

$4x + 4y = 800$

Addition is used, because the trains are heading in opposite directions, which means their distances from the starting point are added together.

Set the two equations up vertically:

$x - y = 16$
$4x + 4y = 800$

We will use elimination to solve for x.

Multiply the entire first equation by 4 so that the coefficients for y will be opposite numbers:

$(x - y = 16) \times 4 = 4x - 4y = 64$

$4x - 4y = 64$
$4x + 4y = 800$

Combine the two equations together to cancel out y:

$8x = 864$

Divide both sides by 8 to get x by itself:

$x = 108$

The speed of the eastbound train is 108 mph.

5 0

3 years ago

Find the distance between e (7,-2) and f (-2,-2)

Anettt [7]

(x,y)
y does't change makes it easier

frm 7 to -2
-2-7=-9
distance is 9

6 0

3 years ago

Number line for 235+123

valentina_108 [34]

I think this is right
all you need to do is:

235-123= 112
then to make sure its correct you do:
123+112= 235

Hope this has helped you. :)

8 0

3 years ago

after 4 new students joined a class,the class had 32 students.Which equation can be used to find n,the number of students in the

OLEGan [10]

Answer....
The answer is

7 0

2 years ago

How to do this question plz answer me ​

How to do this question plz answer me