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GrogVix [38]
3 years ago
8

Suppose y varies directly with x. Write a direct variation equation that relates x and y. Then find the value of y when x = 7.

Mathematics
2 answers:
horsena [70]3 years ago
5 0
From the statement, y varies directly with x. It can be expressed as:

y α x

To change it to an equality, we insert a proportionality constant k.

y = kx

We first solve for k,

8 = k(-4)
k = -2

Therefore, when x = 7,

y = -2(7)
y = -14
Sonja [21]3 years ago
4 0
For direct variation, y = kx
8 = -4k
k = 8/-4 = -2

Therefore, required equation is y = -2x

when x = 7, y = -2(7) = -14
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Independent random samples of vehicles traveling past a given point on an interstate highway have been observed on monday versus
quester [9]
Hi! 

To compare this two sets of data, you need to use a t-student test:

You have the following data:

-Monday n1=16; <span>x̄1=59,4 mph; s1=3,7 mph

-Wednesday n2=20;  </span>x̄2=56,3 mph; s2=4,4 mph

You need to calculate the statistical t, and compare it with the value from tables. If the value you obtained is bigger than the tabulated one, there is a statistically significant difference between the two samples.

t= \frac{X1-X2}{ \sqrt{ \frac{(n1-1)* s1^{2}+(n2-1)* s2^{2} }{n1+n2-2}} * \sqrt{ \frac{1}{n1}+ \frac{1}{n2}} } =2,2510

To calculate the degrees of freedom you need to use the following equation:

df= \frac{ (\frac{ s1^{2}}{n1} + \frac{ s2^{2}}{n2})^{2}}{ \frac{(s1^{2}/n1)^{2}}{n1-1}+ \frac{(s2^{2}/n2)^{2}}{n2-1}}=33,89≈34

The tabulated value at 0,05 level (using two-tails, as the distribution is normal) is 2,03. https://www.danielsoper.com/statcalc/calculator.aspx?id=10

So, as the calculated value is higher than the critical tabulated one, we can conclude that the average speed for all vehicles was higher on Monday than on Wednesday.



5 0
3 years ago
У
Masteriza [31]

Answer:

3 units by 4 units

8 0
3 years ago
Need help ASAP due in 7 minutes <br> Will make you brainlist
Reika [66]

Answer:

A

Step-by-step explanation:

A is the only answer with ordered pairs that have a consistent rate of change, -1/3

6 0
3 years ago
The United States five-dollar bill are 155.956 mm long and 66.294 wide. A stack of these bills fits inside a 156 x 66.3 x 66.3 m
maxonik [38]

Answer:

A) $5 × 25 = $75

B) 37.69%

Step-by-step explanation:

The dimension of five dollar bill:

Length = 155.956mm

Width = 66.294

Volume of box being occupied by 5 dollar bill = 258,473.68mm^3

Dimension of box :

156 x 66.3 x 66.3 mm

If volume of the 5—dollar bill is 258,473.68mm^3

Then, the Thickness of the five dollar stack equals :

Volume = Length × width × height

258,473.68mm^3 = 155.956mm × 66.294 × height

258,473.68 = 10338.947064 × h

h = (258473.68/10338.947064)

h = 25.000000003288 = 25

Therefore, the amount of money in the box is:

$5 × 25 = $75

Percentage of box volume taken up by $5 bill

Volume of the box:

156 x 66.3 x 66.3 mm = 685727.6399mm^3

Volume of box being occupied by 5 dollar bill = 258,473.68mm^3

(258,473.68 / 685727.6399) × 100

=37.69%

4 0
3 years ago
Which expression is equivalent to the square root of 1/8
irina1246 [14]
When you say "which," it sounds like it should be multiple choice. Anyways, here's the simplified form of \sqrt{\frac{1}8}}

\sqrt{\frac{1}8}} = \frac{\sqrt{1}}{\sqrt{8}} = \frac{1}{\sqrt{8}} * \frac{\sqrt{8}}{\sqrt{8}}=\boxed{\frac{\sqrt{8}}8}

(When simplifying fractions, you should <em>never</em> have a square root on the bottom. Multiply by the square root to cancel it out)
4 0
3 years ago
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