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ahrayia [7]
3 years ago
12

What is 300 miles to 210 miles in percent of change

Mathematics
1 answer:
Sergeu [11.5K]3 years ago
7 0

Answer:

The Percent change is -30% (decrease)

In this case we have a negative change (decrease) of -30 percent because the new value is smaller than the old value.

Step-by-step explanation:

Here, To find the percentage change, use this formula

<h3><u>Formula</u>:</h3>

Percent change = New - Old ÷ |Old| × 100%

Percent change = 210 - 300 ÷ |300| × 100%

Percent change = -90/300 × 100%

Percent change = -30% (decrease)

Thus, The Percent change is -30% (decrease)

 

<u>-TheUnknownScientist</u><u> 72</u>

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59:17
poizon [28]

Answer:-13,-25

Step-by-step explanation:

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8 0
3 years ago
Allen�s hummingbird (Selasphorus sasin ) has been studied by zoologist Bill Alther A small group of 15 Allen� s hummingbirds has
Bogdan [553]

Answer:

1) 80% CI: [3.04; 3.26]gr

d= 0.11

2) n= 28 hummingbirds

Step-by-step explanation:

Hello!

The study variable of this experiment is:

X: the weight of a hummingbird. (gr)

And it has a normal distribution, symbolically: X~N(μ;σ²)

And (I hope I got it correctly) its population standard deviation is σ= 0.33

There was a sample of n= 15 hummingbirds taken, its sample mean X[bar]= 3.15 gr

1) You need to construct an 80% Confidence Interval for the population mean of the hummingbird's weight.

Since the study variable has a normal distribution, you can use either the standard normal distribution or the Student's t distribution. Both are useful to estimate the population mean. Since the population standard variance is known, the best choice is the Standard normal.

Z= <u> X[bar] - μ </u>~ N(0;1)

       σ/√n

The formula for the interval is:

X[bar] ± Z_{1- \alpha /2} * (σ/√n)

Z_{1- \alpha /2}= Z_{0.90} = 1.28

3.15 ± 1.28 * (0.33/√15)

[3.04; 3.26]gr

The margin of error (d) of a confidence interval is hal its amplitude (a)

a= Upper bond - Lower bond

d= (Upper bond - Lower bond)/2

d= \frac{(3.26-3.04)}{2} = 0.11

2) You need to calculate a sample size for a 80% Confidence interval for the average weight of the hummingbirds with a margin of error of d= 0.08

As I said before, the margin of error is half the amplitude of the interval, the formula you use to estimate the population mean has the following structure:

"point estamator" ± "margin of error"

Then the margin of error is:

d= Z_{1- \alpha /2} * (σ/√n)

Now what you have to do is rewrite the formula based on the sample size

d= Z_{1- \alpha /2} * (σ/√n)

\frac{d}{Z_{1- \alpha /2}}= σ/√n

√n * \frac{d}{Z_{1- \alpha /2}}= σ

√n = σ * \frac{Z_1- \alpha /2}{d}

n = (σ * \frac{Z_1- \alpha /2}{d})²

n=  (0.33 * \frac{1.28}{0.08})²

n= 27.8784 ≅ 28 hummingbirds.

I hope it helps!

4 0
3 years ago
One month Ivanna rented 7 movies and 9 video games for a total of $80. The next month she rented 5 movies and 3 video games for
ZanzabumX [31]

Answer:

each movie costs $2.75, each video game costs $6.75

Step-by-step explanation:

x = movies, y = video games

7x + 9y = 80

5x + 3y = 34

simplified to

x = 11/4 , y = 27/4

5 0
3 years ago
Cmon fwm on dis one to
stich3 [128]

Answer:

x = 10.5

Step-by-step explanation:

we know that ZP = PX (its the midpoint of the rectangle)

11 = PX

ZP + PX = ZX

11+11 = ZX

22 = ZK

2x + 1 = 22

2x = 22 -1

2x = 21

x = 21/2

x = 10.5

3 0
3 years ago
In parallelogram LMNO, what is the measure of angle N?<br><br> 50°<br> 70°<br> 110°<br> 130°
belka [17]

we know that

In a parallelogram opposite angles are congruent and consecutive angles are supplementary.

So

m∠O=m∠M

m∠L=m∠N

m∠O+m∠L=180

Step 1

Find the value of x

(x+20)+(2x+10)=180\\ 3x+30=180\\ 3x=180-30\\ x=\frac{150}{3} \\ \\ x=50\ degrees

Step 2

Find the value of angle L

m∠L=(2x+10)

m∠L=(2*50+10)

m∠L=110\ degrees

Remember that

m∠N=m∠L

m∠N=110\ degrees

therefore

the answer is

the measure of the angle N is equal to 110\ degrees





4 0
3 years ago
Read 2 more answers
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