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3 years ago

Cuantas clases de progresiones conoces

Mathematics

1 answer:

kozerog [31]3 years ago

8 0

Answer:ninguna

Step-by-step explanation:

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30 PTS!!!!! Cole needs to include at least 11 mg and at most 22 mg of iron in his diet each day. Cole plans to eat multiple ba

ser-zykov [4K]

Answer:

See explanation

Step-by-step explanation:

Part A: If Cole eats 3 bananas each day. These 3 bananas contain $3\cdot 0.3=0.9$ mg of iron.

Let x be the number of vitamins Cole takes. Each whole vitamin contains 4 mg of iron, then x vitamins contain 4x mg of iron.

The total amount of iron Cole takes is

$0.9+4x\ mg$

Cole needs to include at least 11 mg and at most 22 mg of iron in his diet each day, so

$11\le 0.9+4x\le 22$

Solve it:

$11-0.9\le 4x\le 22-0.9\\ \\10.1\le 4x\le 21.1\\ \\2.525\le x\le 5.275$

The smallest number of vitamins - 3, the greatest number of vitamins - 5.

Part B: Cole continues to eat 3 bananas each day. He pays $\$2\cdot 7=\$14$ for bananas per week.

If Cole spends a total of $20 on bananas and vitamins this week, then he spent $20 - $14 = $6 on vitamins.

Let x be the number of vitamins Cole takes this week.

First 10 vitamins are free, then x - 10 vitamins each cost $0.50 (he pays an additional dollar for every 2 additional vitamins he purchases) and they cost

$\$0.50(x-10)$

This amount of money is exactly $6, so

$0.50(x-10)=6\\ \\5(x-10)=60\\ \\x-10=12\\ \\x=22$

This means Cole takes 3 vitamins per day (the whole number) and he is able to meet his iron requirement every day this week, based on answer in Part A.

5 0

3 years ago

Read 2 more answers

Find the surface area of the triangular prism (above) using its net (below).

vovangra [49]

Answer:

96 cm^2 (centimetres squared)

Step-by-step explanation:

(7 x 3) x 2 = 42

6x2 / 2 x 2 = 12

6 x 7 = 42

42 + 12 + 42 = 96 cm^2

3 0

3 years ago

Read 2 more answers

Which ones are correct?

emmasim [6.3K]

Answer:

Th answer is D

Step-by-step explanation:

7 0

3 years ago

A quality control expert at LIFE batteries wants to test their new batteries. The design engineer claims they have a variance of

yan [13]

Answer:

"The probability that the mean battery life would be greater than 948.8 minutes" is 0.1446.

Step-by-step explanation:

In this case, the quality control expert takes a sample of batteries. From these batteries, we want to find "the probability that the mean battery life would be greater than 948.8 minutes".

Different concepts needed to take into account to solve this question

Sampling Distribution of the Means

For doing this, we need to use the sampling distribution of the means, which results from taking the mean for each possible sample coming from a random variable $\\ x$ . Roughly speaking, each sample will have a different mean, $\\ \overline{x}$ , and the probability distribution for any of these means is called the sampling distribution of the means.

The sampling distribution of the means has a mean that equals the population's mean for the random variable $\\ x$ , i.e., $\\ \mu$ , and its standard deviation is $\\ \frac{\sigma}{\sqrt{n}}$ . We can express this mathematically as:

$\\ \overline{x} \sim N(\mu, \frac{\sigma}{\sqrt{n}})$ [1]

Standardized Values for $\\ \overline{x}$

We can standardized the values for $\\ \overline{x}$ using z-scores:

$\\ Z = \frac{\overline{x} - \mu}{\frac{\sigma}{\sqrt{n}}}$ [2]

This random variable $\\ Z$ follows a standard normal distribution, that is, $\\ Z \sim N(0,1)$ , and it is easier to find probabilities since the values for them are tabulated in the standard normal table (available in any Statistics book or on the Internet.)

What type of distribution follows the sampling distribution of the means?

A general rule of thumb is that this distribution (the sampling distribution of the means) follows a normal distribution if the sample size, $\\ n$ , is bigger than or equal to 30 observations, or $\\ n \geq 30$ . In this case, $\\ n = 109$ batteries. This is a result from the Central Limit Theorem, fundamental in Statistical Inference.

Standard Deviation

We have to remember that the standard deviation is the square root of the variance $\\ \sigma^2$ , or $\\ \sqrt{\sigma^2}$ .

$\\ \sigma^{2} =5929$
$\\ \sigma = \sqrt{5929} = 77$

Therefore, the standard deviation in this case is $\\ \sigma = 77$ minutes.

In sum, we have the following information to answer this question:

$\\ \sigma = 77$ minutes.
$\\ \mu = 941$ minutes.
$\\ n = 109$ batteries (the sample size is large enough to assume that the sampling distribution of the means follows a normal distribution).
$\\ \overline{x} = 948.8$ minutes.

What is the probability that the mean battery life would be greater than 948.8 minutes?

Well, having all the previous information, we can use [2] to solve this question (without using units):

$\\ z = \frac{\overline{x} - \mu}{\frac{\sigma}{\sqrt{n}}}$

$\\ z = \frac{948.8 - 941}{\frac{77}{\sqrt{109}}}$

$\\ z = \frac{7.8}{\frac{77}{\sqrt{109}}}$

$\\ z = \frac{7.8}{7.37526}$

$\\ z = 1.05758 \approx 1.06$

This result is the standardized value or z-score for $\\ \overline{x}$ , considering $\\ \mu = 941$ and $\\ \sigma = 77$ .

We round z to two decimals digits since standard normal table only uses it as an entry to find probabilities.

With $\\ z = 1.06$ , we can consult the cumulative standard normal table. First, we need to find with $\\ z = 1.0$ in the first column in the table. Then, in its first raw, we need to find +0.06. The intersection for these two values determines the cumulative probability for $\\ P(z$ .