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2 years ago

Quickly helllllpppp! plz

Mathematics

1 answer:

xz_007 [3.2K]2 years ago

7 0

Answer:

≈ 8.07 mg

Step-by-step explanation:

Given

f(x) = 12 $(0.82)^{x}$

Substitute x = 1 into f(x) , that is

f(2) = 12(0.82)² = 12 ×0.6724 ≈ 8.07 mg

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Tony is pouring milk for student lunches. She knows that 3 quarts of milk contain 12 cups. How many cups can she pour with 7 qua

Evgesh-ka [11]

Answer:

7 quarts = 28 cups

10 cups = 2.5 quarts

Step-by-step explanation:

In order to solve the two different questions in the problem, starting with a ratio of the number of quarts to the number of cups would be helpful:

$\frac{quarts}{cups}=\frac{3}{12}=\frac{1}{4}$

So, for every 1 quart of milk, she can pour 4 cups. Using this ratio, we can set up equivalent ratios, or proportions, to solve for the missing value. For the first question, we need to know that amount of cups in 7 quarts:

$\frac{1}{4}=\frac{7}{x}$

We can solve for 'x' by multiplying the numerator and denominator by the same factor, in this case '7'. So, 4 x 7 = 28 cups.

Next, we need to solve for the amount of quarts needed for 10 cups:

$\frac{1}{4}=\frac{x}{10}$

4 x 2.5 = 10, so we need to multiply the numerator by 2.5: 1 x 2.5 = 2.5 quarts.

5 0

2 years ago

You want to obtain a sample to estimate a population mean. Based on previous evidence, you believe the population standard devia

Arturiano [62]

Answer:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (3)

$n=(\frac{2.58(54.5)}{5})^2 =790.846 \approx 791$

So the answer for this case would be n=791 rounded up to the nearest integer

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

$\bar X$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

s represent the sample standard deviation

n represent the sample size

Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

Since the Confidence is 0.99 or 99%, the value of $\alpha=0.01$ and $\alpha/2 =0.005$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.005,0,1)".And we see that $z_{\alpha/2}=2.58$

The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (2)

And on this case we have that ME =+5 and we are interested in order to find the value of n, if we solve n from equation (2) we got:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (3)

$n=(\frac{2.58(54.5)}{5})^2 =790.846 \approx 791$

So the answer for this case would be n=791 rounded up to the nearest integer

4 0

3 years ago

Which expression is equivalent to<br> 10x5<br> 54x9<br> ? Assume x=0.

malfutka [58]

10x5 is the best soulition !

7 0

3 years ago

What is the answer to (3 × 144) × 199

vlada-n [284]

Answer:

The answer will be 85,968

3 0

2 years ago

Read 2 more answers

The book store is having a sale where all hardcover books are 20% off. Jamie also has a coupon for 15% off any fiction book. Jam

scoray [572]

You can use the fact that both 20% and 15% discounts will be merged to reduce 35% of the price of the book that Jamie buys.

By buying the book on sale and using the coupon, Jamie will save

Option B: $11.55

<h3>
How are discounts calculated for the case when its sale and we've got discount coupons too?</h3>

Suppose the sale gives p% off.

And the discount coupon provides q% off.

Then we have total discount applied on the cost of the object bought as

(p+q)%

<h3>How to find the percentage from the total value?</h3>

Suppose the value of which a thing is expressed in percentage is "a'

Suppose the percent that considered thing is of "a" is b%

Then since percent shows per 100 (since cent means 100), thus we will first divide the whole part in 100 parts and then we multiply it with b so that we collect b items per 100 items(that is exactly what b per cent means).

Thus, that thing in number is

$\dfrac{a}{100} \times b$

<h3>Using the above fact to calculate the amount that Jamie saved </h3>

Since the sale offers 20% discount and Jamie has got 15% discount coupon for any fiction book, thus, total 35% will be discounted if Jamie buys fiction book.

Since the price of the fiction book that Jamie brought is $32.99, thus,

Saved amount = 35% of $32.99 = $\dfrac{32.99}{100} \times 35 = 0.3299 \times 35 \approx \$11.55$

Thus,

By buying the book on sale and using the coupon, Jamie will save

Option B: $11.55

<h3 />

Learn more about percentage here:

brainly.com/question/11549320

5 0

2 years ago