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OLEGan [10]
1 year ago
8

Rachael ordered early learning software for her daughter from an online retailer. Each item costs $6.50, and there is a shipping

fee of $8.50 for the entire order.
a. What is the cost of Rachel's order if she buys 7 items? Show your work and label.

b. Write an equation to describe this situation. Let s represent the number of software items ordered and c represent the total cost of the order.

c. Use your equation to determine how many items Rachel ordered if her total cost was $80. Show your work and label.
Mathematics
2 answers:
Tju [1.3M]1 year ago
8 0

Answer:

Step-by-step explanation:

Each item costs $6.50, and there is a shipping fee of $8.50 for the entire order.

a) if she buys 7 items, the cost of the item would be

(7 × 6.5) + 8.5

= $54

b) Let s represent the number of software items ordered and c represent the total cost of the order. Therefore, the equation describing this situation is

6.5s + 8.5

c) if her total cost was $80, it means that

6.5s + 8.5 = 80

6.5s = 80 - 8.5

6.5s = 71.5

s = 71.5/6.5

s = 11

She ordered 11 items.

natta225 [31]1 year ago
4 0

Answer:

Step-by-step explanation:

(a)

Total cost = (7 items * Cost per item) + Shipping fee = 7*6.5 + 8.5 = $54

(b)

Modelling the above equation with symbols:

c = s*6.5 + 8.5 = 6.5s + 8.5

(c)

For a total cost of 80$, c = 80:

80 = 6.5s + 8.5

Calculating, we get:

s =  11 items

Rachel ordered a total of 11 items

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Answer:

(a) The 90% confidence interval is: (0.60, 0.63) Correct interpretation is (3).

(b) The 95% confidence interval is: (0.42, 0.46) Correct interpretation is (1).

(c) First, the confidence level in part(b) is <u>more than</u> the confidence level in part(a) is, so the critical value of part(b) is <u>more than</u> the critical value of part(a), Second the <u>margin of error</u> in part(b) is <u>more than</u> than in part(a).

Step-by-step explanation:

(a)

Let <em>X</em> = number of dog owners who take more pictures of their dog than of their significant others or friends.

Given:

<em>X</em> = 610

<em>n</em> = 1000

Confidence level = 90%

The (1 - <em>α</em>)% confidence interval for population proportion is:

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

The sample proportion is:

\hat p=\frac{X}{n}=\frac{610}{1000}=0.61

The critical value of <em>z</em> for a 90% confidence level is:

z_{\alpha/2}=z_{0.10/2}=z_[0.05}=1.645

Construct a 90% confidence interval for the population proportion of dog owners who take more pictures of their dog than their significant others or friends as follows:

CI=\hat p\pm z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}\\=0.61\pm 1.645\sqrt{\frac{0.61(1-0.61}{1000}}\\=0.61\pm 0.015\\=(0.595, 0.625)\\\approx(0.60, 0.63)

Thus, the 90% confidence interval for the population proportion of dog owners who take more pictures of their dog than their significant others or friends is (0.60, 0.63).

<u>Interpretation</u>:

There is a 90% chance that the true proportion of dog owners who take more pictures of their dog than of their significant others or friends falls within the interval (0.60, 0.63).

Correct option is (3).

(b)

Let <em>X</em> = number of dog owners who are more likely to complain to their dog than to a friend.

Given:

<em>X</em> = 440

<em>n</em> = 1000

Confidence level = 95%

The (1 - <em>α</em>)% confidence interval for population proportion is:

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

The sample proportion is:

\hat p=\frac{X}{n}=\frac{440}{1000}=0.44

The critical value of <em>z</em> for a 95% confidence level is:

z_{\alpha/2}=z_{0.05/2}=z_{0.025}=1.96

Construct a 95% confidence interval for the population proportion of dog owners who are more likely to complain to their dog than to a friend as follows:

CI=\hat p\pm z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}\\=0.44\pm 1.96\sqrt{\frac{0.44(1-0.44}{1000}}\\=0.44\pm 0.016\\=(0.424, 0.456)\\\approx(0.42, 0.46)

Thus, the 95% confidence interval for the population proportion of dog owners who are more likely to complain to their dog than to a friend  is (0.42, 0.46).

<u>Interpretation</u>:

There is a 95% chance that the true proportion of dog owners who are more likely to complain to their dog than to a friend falls within the interval (0.42, 0.46).

Correct option is (1).

(c)

The confidence interval in part (b) is wider than the confidence interval in part (a).

The width of the interval is affected by:

  1. The confidence level
  2. Sample size
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The confidence level in part (b) is more than that in part (a).

Because of this the critical value of <em>z</em> in part (b) is more than that in part (a).

Also the margin of error in part (b) is 0.016 which is more than the margin of error in part (a), 0.015.

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Step-by-step explanation:

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Answer:

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Mathematically,

H₀: μ₀ = 0.53

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Answer:

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Step-by-step explanation:

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So the equation of the function is \frac{y-4}{4-(-2)} = \frac{x-0}{0-(-6)}

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Again the function g(x) passes through the points (0,4) and (-2,-2).

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Therefore, g(x) = 3x + 4 = f(3x) {from equation (1).

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