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3 years ago

HURRY UP PLZZZZZI NEED TO FINISHHHHI WILL MARK BRAINLYEST!!!:)

Mathematics

2 answers:

Vilka [71]3 years ago

5 0

Answer:

The answer is $300

Step-by-step explanation:

15 dollars per lawn times 5 lawns per day is $75 and 75×4 is 300

andriy [413]3 years ago

4 0

Answer:

I think 60

Step-by-step explanation:

have a great day

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The height is 0.666 kilometers or 666 meters

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3 years ago

A stone is thrown upward from ground level. With what minimum speed should the stone be thrown so as to reach a height of 36 fee

rusak2 [61]

V^2 = u^2 - 2gh; where v is the final speed, u is the initial speed, g = 9.8 m/s = 0.54 ft/min is the accerelation due to gravity, h = height.
At the maximum height, the final speed is 0.
u^2 = 2gh = 2 x 0.54 x 36 = 38.58
u = sqrt(38.58) = 6.21 ft/min

Therefore, the stne should be thrown with 6.21 ft/min

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3 years ago

Andre has been practicing his math facts. He can now complete 135 multiplication

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A. Andre can answer 1.5 facts per second.
135 : 90

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3 years ago

50 POINTS!!! ASAP plz answer all questions will give brainiest!!!!

Sedaia [141]

Answer:

1. $27x^{2} -78x+16$

2. not completely sure but i think its $x= -2 + 3i$

3.x = 2 i √ 5 , − 2 i √ 5

4.x = − 9 ± √ 73 /2

5. Im not sure...

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3 years ago

The U.S. Center for Disease Control reports that the mean life expectancy was 47.6 years for whites born in 1900 and 33.0 years

inn [45]

Answer:

b. The null and alternative hypothesis are:

$H_0: \mu_1-\mu_2=0\\\\H_a:\mu_1-\mu_2\neq 0$

c. Student's t distribution, as it is a two-sample test for the difference between means.

d. Test statistic t = 5.42.

P-value = 0

e. They appear to be significantly different, as the sample data gives strong evidence that the difference is greater than 0.

Step-by-step explanation:

This is a hypothesis test for the difference between populations means.

The claim is that the mean life spans in the county is significantly different for whites and nonwhites.

Then, the null and alternative hypothesis are:

$H_0: \mu_1-\mu_2=0\\\\H_a:\mu_1-\mu_2\neq 0$

The significance level is 0.05.

The sample 1 (white), of size n1=124 has a mean of 45.3 and a standard deviation of 12.7.

The sample 2 (non-white), of size n2=82 has a mean of 34.1 and a standard deviation of 15.6.

The difference between sample means is Md=11.2.

$M_d=M_1-M_2=45.3-34.1=11.2$

The estimated standard error of the difference between means is computed using the formula:

$s_{M_d}=\sqrt{\dfrac{\sigma_1^2}{n_1}+\dfrac{\sigma_2^2}{n_2}}=\sqrt{\dfrac{12.7^2}{124}+\dfrac{15.6^2}{82}}\\\\\\s_{M_d}=\sqrt{1.301+2.968}=\sqrt{4.269}=2.066$

Then, we can calculate the t-statistic as:

$t=\dfrac{M_d-(\mu_1-\mu_2)}{s_{M_d}}=\dfrac{11.2-0}{2.066}=\dfrac{11.2}{2.066}=5.42$

The degrees of freedom for this test are:

df=n_1+n_2-2=124+82-2=204

This test is a two-tailed test, with 204 degrees of freedom and t=5.42, so the P-value for this test is calculated as (using a t-table):

$\text{P-value}=2\cdot P(t>5.42)=0.0000002$

As the P-value (0.0000002) is smaller than the significance level (0.05), the effect is significant.

The null hypothesis is rejected.

There is enough evidence to support the claim that the mean life spans in the county is significantly different for whites and nonwhites.

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3 years ago