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2 years ago

Plz :<

Mathematics

1 answer:

insens350 [35]2 years ago

5 0

Answer:

D 8 hours

Step-by-step explanation:

it has to be positive and it is obviously more than 1 hour so it has to be 8 hours by process of elimination.

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Anybody know how to work on decay rate? I'll give brainliest. THIS IS DUE SOON SO PLEASE HELP

artcher [175]

Answer:

28%

Step-by-step explanation:

In the function the .72 means that each unit of time 72% of the value is retained. This means that 28% percent of the value is lost or decays because 1-0.72=0.28 or 28 percent.

3 0

3 years ago

What's the answer to the math problem 8r+4=10+2r

mart [117]

In order to solve for r you have to place all the number in one side. then isolate r ...... r=1

6 0

3 years ago

The Johnson twins were born nine years after their older sister. This year, the product of the three siblings ages is exactly 18

KATRIN_1 [288]

Answer: The age of the twins is 10 years.

Step-by-step explanation:

Suppose the age of older sister be x

Let the age of twins sister be x-9, as they are born after 9 years.

Product of their ages be

$x(x-9)(x-9)\\\\=x(x^2-18x+81)\\\\=x^3-18x^2+81x$

Sum of their ages will be

$x+x-9+x-9\\\\=3x-18$

According to question,

$1861+3x-18=x^3-18x^2+81x\\\\x^3-18x^2+81x-3x+18-1861=0\\\\x^3-18x^2+78x-1843=0\\\\x=19$

So, Age of older sister will be 19 years.

Age of the twins will be

$19-9=10\ years$

Hence, the age of the twins is 10 years.

3 0

3 years ago

An article regarding interracial dating and marriage recently appeared in the Washington Post. Of the 1,709 randomly selected ad

VMariaS [17]

Answer:

The 95% confidence interval for the percent of all black adults who would welcome a white person into their families is (0.8222, 0.8978).

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which

z is the zscore that has a pvalue of $1 - \frac{\alpha}{2}$ .

For this problem, we have that:

323 blacks, 86% of blacks said that they would welcome a white person into their families. This means that $n = 323, p = 0.86$

95% confidence level

So $\alpha = 0.05$ , z is the value of Z that has a pvalue of $1 - \frac{0.05}{2} = 0.975$ , so $Z = 1.96$ .

The lower limit of this interval is:

$\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.86 - 1.96\sqrt{\frac{0.86*0.14}{323}} = 0.8222$

The upper limit of this interval is:

$\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.86 + 1.96\sqrt{\frac{0.86*0.14}{323}} = 0.8978$

The 95% confidence interval for the percent of all black adults who would welcome a white person into their families is (0.8222, 0.8978).

5 0

3 years ago

A manufacturer has designed a process to produce pipes that are 10 feet long. The distribution of the pipe length, however, is a

Lina20 [59]

Answer:

first of all, this person is a hacker, their malicious files will destroy your computer

Step-by-step explanation:

B is the answer I think

8 0

3 years ago