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3 years ago

Responda: Por favor, é urgente.

Mathematics

1 answer:

kumpel [21]3 years ago

5 0

Answer:

C) CA=40

Step-by-step explanation:

2y/(2y+4)=(2y+6)/4y

cross multiply

8y²=4y²+20y+24

4(2y²)=4(y²+5y+6)

divide both sides by 4

2y²=y²+5y+6

y²-5y-6=0

(y-6)(y+1)=0

So the answer must be either 6 or -1. Since it can't be a negative number, it must be 6.

CA=2(6)+4+4(6)

CA=12+4+24

CA=40

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Three friends went apple picking and then counted the apples they picked.

Marizza181 [45]

Answer:

Carmen has the biggest red to green apple ratio

Step-by-step explanation:

Red to green apple ratios are, in order, 20:12, (5:3), 12:10 (6:5), and 16:20 (4:5). 5:3 is the biggest red to green apple ratio because for every 5 red apples Carmen has 3 green apples.

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3 years ago

Repeated student samples. Of all freshman at a large college, 16% made the dean’s list in the current year. As part of a class p

Dima020 [189]

Answer:

a) p-hat (sampling distribution of sample proportions)

b) Symmetric

c) σ=0.058

d) Standard error

e) If we increase the sample size from 40 to 90 students, the standard error becomes two thirds of the previous standard error (se=0.667).

Step-by-step explanation:

a) This distribution is called the sampling distribution of sample proportions (p-hat).

b) The shape of this distribution is expected to somewhat normal, symmetrical and centered around 16%.

This happens because the expected sample proportion is 0.16. Some samples will have a proportion over 0.16 and others below, but the most of them will be around the population mean. In other words, the sample proportions is a non-biased estimator of the population proportion.

c) The variability of this distribution, represented by the standard error, is:

$\sigma=\sqrt{p(1-p)/n}=\sqrt{0.16*0.84/40}=0.058$

d) The formal name is Standard error.

e) If we divided the variability of the distribution with sample size n=90 to the variability of the distribution with sample size n=40, we have:

$\frac{\sigma_{90}}{\sigma_{40}}=\frac{\sqrt{p(1-p)/n_{90}} }{\sqrt{p(1-p)/n_{40}}}}= \sqrt{\frac{1/n_{90}}{1/n_{40}}}=\sqrt{\frac{1/90}{1/40}}=\sqrt{0.444}= 0.667$

If we increase the sample size from 40 to 90 students, the standard error becomes two thirds of the previous standard error (se=0.667).

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3 years ago

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Elena L [17]

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4 years ago

The circumference of the bike tire above is 83.524 inches. What is the radius of the bike tire? (Use 3.14 for .) A. 262.27 in B.

Shtirlitz [24]

Answer:

Option C. 13.3 in.

Step-by-step explanation:

Here's the required formula to find the radius of the bike tire :

$\longrightarrow{\pmb{\sf{C_{(Circle)} = 2\pi r}}}$

C = circumference
π = 3.14
r = radius

Substituting all the given values in the formula to find the radius of the bike tire :

$\begin{gathered} \qquad{\longrightarrow{\sf{C_{(Circle)} = 2\pi r}}} \\ \\ \qquad{\longrightarrow{\sf{83.524 = 2 \times 3.14 \times r}}} \\ \\ \qquad{\longrightarrow{\sf{83.524 = 6.28 \times r}}} \\ \\ \qquad{\longrightarrow{\sf{83.524 = 6.28r}}} \\ \\ \qquad{\longrightarrow{\sf{r = \frac{83.524}{6.28}}}} \\ \\ \qquad{\longrightarrow{\sf{r = 13.3 \: in}}} \\ \\ \qquad \star{\underline{\boxed{\sf{\red{r = 13.3 \: in}}}}}\end{gathered}$

Hence, the radius of bike tire is 13.3 inches.

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