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3 years ago

9th grade math thanks

Mathematics

2 answers:

zmey [24]3 years ago

6 0

Answer:

Step-by-step explanation:

For plumber A : y = 100 + 30x

For plumber B :

Let the total charge be y

Initial charge be x

Hourly rate be za

For total price = 105 in 1hr

105 = x + a ........(1)

For 160 total charge in 2hrs

160 = x + 2a .........(2)

Substracting (1) from (2)

160 - 105 = 2a - a

55 = a

Substituting a = 55 in (1)

105 = x + a

105 = x + 55

x = 105 - 55

x = 50

:- equation for total charge is

y = 50 + 55a

ale4655 [162]3 years ago

3 0

Answer:

Plumber A has greater initial fee

Step-by-step explanation:

Plumber B:

Hourly charge = 160 - 105 = $55

Initial charge = 105 - 55 = $50

Equation: y = 50 + 55x

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What adds to 6 and multiplies to 18

kirill115 [55]

That has to be impossible because you can’t get any solution that would possible add to 6

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3 years ago

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there is a rectangle built with 12 tiles in this rectangle half of the tiles are red one fourth of the tiles are yellow and one

yarga [219]

There are 6 red tiles since 6 is half of 12. 1/4 of 12 is 3 (divide 12 by 4), so there are 3 green tiles and 3 yellow tiles

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4 years ago

The circumference of the earth is 2.4x109 miles. if you traveled at an average of 8.5x10 miles per hour, how long would it take

pshichka [43]

Answer:

282 hr <======= see below

Step-by-step explanation:

Distance / rate = time

2.4 x 10^9 mi / 85 m/hr = 28235294 hr

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probably should be 8.5 x 10^6 perhaps? then answer is 282

<h3>If speed was 8.5 x 10^5 then answer becomes ~ 2820 </h3>

8 0

2 years ago

Conservationists have despaired over destruction of tropical rain forest by logging, clearing, and burning." These words begin a

IgorLugansk [536]

Answer: -8.16 to 15.84

Step-by-step explanation: <u>Confidence</u> <u>Interval</u> is an interval in which we are a percentage sure the true mean is in the interval.

A confidence interval for a difference between two means and since sample 1 and sample 2 are under 30, will be

$x_{1}-x_{2}$ ± $t.S_{p}\sqrt{\frac{1}{n_{1}}+\frac{1}{n_{2}} }$

where

x₁ and x₂ are sample means

t is t-score

$S_{p}$ is estimate of standard deviation

n₁ and n₂ are the sample numbers

The estimate of standard deviation is calculated as

$S_{p}=\sqrt{\frac{(n_{1}-1)s_{1}^{2}+(n_{2}-1)s_{2}^{2}}{n_{1}+n_{2}-2} }$

where

s₁ and s₂ are sample standard deviation of each sample

Degrees of freedom is:

$df=n_{1}+n_{2}-2$

df = 12 + 9 - 2

df = 19

Checking t-table, with 90% Confidence Interval and df = 19, t = 1.729.

The mean and standard deviation for 12 unlogged forest plots are 17.5 and 3.53, respectively.

The mean and standard deviation for 9 logged plots are 13.66 and 4.5, respectively.

Calculating estimate of standard deviaton:

$S_{p}=\sqrt{\frac{(12-1)(3.53)^{2}+(9-1)(4.5)^{2}}{12+9-2} }$

$S_{p}=\sqrt{\frac{299.07}{19} }$

$S_{p}=$ 15.74

The difference between means is

$x_{1}-x_{2}$ = 17.5 - 13.66 = 3.84

Calculating the interval:

$t.S_{p}\sqrt{\frac{1}{n_{1}}+\frac{1}{n_{2}} }$ = $1.729.15.74.\sqrt{\frac{1}{12} +\frac{1}{9} }$

$t.S_{p}\sqrt{\frac{1}{n_{1}}+\frac{1}{n_{2}} }$ = $27.21\sqrt{\frac{21}{108} }$

$t.S_{p}\sqrt{\frac{1}{n_{1}}+\frac{1}{n_{2}} }$ = $27.21\sqrt{0.194}$

$t.S_{p}\sqrt{\frac{1}{n_{1}}+\frac{1}{n_{2}} }$ = 12

Then, interval for the difference in mean is 3.84 ± 12, which means the interval is between:

lower limit: 3.84 - 12 = -8.16

upper limit: 3.84 + 12 = 15.84

The interval is from -8.16 to 15.84.

5 0

3 years ago

<img src="https://tex.z-dn.net/?f=y%20%3D%20%20%5Cfrac%7B1%7D%7B5%7D%20x%20-%206" id="TexFormula1" title="y = \frac{1}{5} x - 6

Helen [10]

Answer:

Step-by-step explanation:

I'm guessing you want a graph? I can't give you one, but I can help you make one.

To find intercepts, plug in zero for the opposite variable. So:

y-int: y=(1/5)0-6

y=-6. The y-int point is (0,-6)

x-int: 0=(1/5)x-6

6=(1/5)x

30=x. The x-int point is (30, 0)

Also, the slope is 1/5, so you go up 1, go right 5. This should help :))

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3 years ago