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3 years ago

Tell me if i did these correctly and i will mark you brainiest

Mathematics

1 answer:

Lana71 [14]3 years ago

7 0

Answer:

You only got 7, 8, and 9 wrong

Step-by-step explanation:

it said convert to percents not fractions. Number 7 is 35%, number 8 is 80%, and number 9 is 126%

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A car company took a random sample of 85 people and asked them whether they have a plan to purchanse an electrinic car in the ne

lutik1710 [3]

Answer:

We have 96% of confidence that the true proportion of people who responded that they have a plan to buy one electric car is between (0.121 and 0.303).

Step-by-step explanation:

For this case the estimated proportion of people who responded that they have a plan to buy one electric car is given by:

$\hat p = \frac{X}{n}= \frac{18}{85}=0.212$

Where X represent the number of people who responded that they have a plan to buy one and n represent the sample size selected

We know that the confidence level for this case is 96% of confidence, then our significance level would be $\alpha=1-0.96=0.04$ and $\alpha/2 =0.02$ . And the critical value would be:

$z_{\alpha/2}=-2.05, z_{1-\alpha/2}=2.05$

The confidence interval for the true proportion is given by this expression:

$\hat p \pm z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$

Replacing the data given we got:

$0.212 - 2.05\sqrt{\frac{0.212(1-0.212)}{85}}=0.121$

$0.212 + 2.05\sqrt{\frac{0.212(1-0.212)}{85}}=0.303$

We have 96% of confidence that the true proportion of people who responded that they have a plan to buy one electric car is between (0.121 and 0.303).

6 0

4 years ago

3. A rare species of aquatic insect was discovered in the Amazon rainforest. To protect the species, environmentalists declared

navik [9.2K]

The number of months until the insect population reaches 40 thousand is 14.29 months and the limiting factor on the insect population as time progresses is 250 thousands.

Given that population P(t) (in thousands) of insects in t months after being transplanted is P(t)=(50(1+0.05t))/(2+0.01t).

(a) Firstly, we will find the number of months until the insect population reaches 40 thousand by equating the given population expression with 40, we get

P(t)=40

(50(1+0.05t))/(2+0.01t)=40

Cross multiply both sides, we get

50(1+0.05t)=40(2+0.01t)

Apply the distributive property a(b+c)=ab+ac, we get

50+2.5t=80+0.4t

Subtract 0.4t and 50 from both sides, we get

50+2.5t-0.4t-50=80+0.4t-0.4t-50

2.1t=30

Divide both sides with 2.1, we get

t=14.29 months

(b) Now, we will find the limiting factor on the insect population as time progresses by taking limit on both sides with t→∞, we get

$\begin{aligned}\lim_{t \rightarrow \infty}P(t)&=\lim_{t \rightarrow \infty}\frac{50(1+0.05t)}{2+0.01t}\\ &=\lim_{t \rightarrow \infty}\frac{50(\frac{1}{t}+0.05)}{\frac{2}{t}+0.01}\\ &=50\times \frac{0.05}{0.01}\\ &=250\end$

(c) Further, we will sketch the graph of the function using the window 0≤t≤700 and 0≤p(t)≤700 as shown in the figure.

Hence, when the population P(t) (in thousands) of insects in t months after being transplanted by P(t)=(50(1+0.05t))/(2+0.01t) then the number of months until the insect population reaches 40 thousand 14.29 months and the limiting factor on the insect population is 250 thousand and the graph is shown in the figure.

Learn more about limiting factor from here brainly.com/question/18415071.

#SPJ1

8 0

2 years ago

Mr. Ravenhead's car averages 23.75 miles per gallon of gasoline. Express this amount as a mixed number in simplest form

lisabon 2012 [21]

A mixed number consists of a whole number and a fraction.

23.7523 will be the whole number.
0.75 will be the fraction.

To convert 0.75 into a fraction, set it over 100 and simplify.

$\frac{75}{100} = \frac{75:25}{100:25} = \frac{3}{4}$

$23 \frac{3}{4}$

4 0

4 years ago

How much would d dollars earn in one year at the rate of p percent compounded annually

Elenna [48]

Answer:

Step-by-step explanation:

Adapt the compound amount formula to this situation:

A = P(1 + r)^t becomes A = d(1 + p/100)^1, or just A = d(1 + p/100)

5 0

3 years ago

How do I find the surface area of a rectangle ?

notsponge [240]

Answer:

The picture

Step-by-step explanation:

7 0

3 years ago