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2 years ago

5

Heather paid $2,022.30 for a computer. If the price paid includes a 7% sales tax, which if the following equation can be used to

determine the price of the computer after tax?
(Let x represent the cost of the computer and y represent the total cost after tax.)

2 answers:

Yuliya22 [10]2 years ago

4 0

Answer:

D) $y=1.07x$

Step-by-step explanation:

The Total cost, price plus taxes, will given by

1) Dividing the tax 7 by 100, and write it in its decimal form:

$\frac{7}{100}=0.07$

2) Add the number 1, and make it a constant

$0.07+1=1.07 \Rightarrow y=1.07x$

This function fits to calculate the total cost after a 7% tax. In this case just plug $2,022.30 for x, then solve for y to have the total cost.

$y=1.07(2,022.30)=\$2,163.86$

andrey2020 [161]2 years ago

3 0

Answer:

B

Step-by-step explanation:

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Leona [35]

Answer:

$z=\frac{(33-31)-0}{\sqrt{\frac{8^2}{330}+\frac{7^2}{310}}}}=3.37$

$p_v =P(Z>3.37)=1-P(Z$

Comparing the p value with a significance level for example $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and we can say that the mean for the Campus 1 is significantly higher than the mean for the group 2.

Step-by-step explanation:

Data given

Campus Sample size Mean Population deviation

1 330 33 8

2 310 31 7

$\bar X_{1}=33$ represent the mean for sample 1

$\bar X_{2}=31$ represent the mean for sample 2

$\sigma_{1}=8$ represent the population standard deviation for 1

$\sigma_{2}=7$ represent the population standard deviation for 2

$n_{1}=330$ sample size for the group 1

$n_{2}=310$ sample size for the group 2

$\alpha$ Significance level provided

z would represent the statistic (variable of interest)

Concepts and formulas to use

We need to conduct a hypothesis in order to check if the mean for Campus 1 is higher than the mean for Campus 2, the system of hypothesis would be:

Null hypothesis: $\mu_{1}-\mu_{2}\leq 0$

Alternative hypothesis: $\mu_{1} - \mu_{2}> 0$

We have the population standard deviation's, and the sample sizes are large enough we can apply a z test to compare means, and the statistic is given by:

$z=\frac{(\bar X_{1}-\bar X_{2})-\Delta}{\sqrt{\frac{\sigma^2_{1}}{n_{1}}+\frac{\sigma^2_{2}}{n_{2}}}}$ (1)

z-test: Is used to compare group means. Is one of the most common tests and is used to determine whether the means of two groups are equal to each other.

With the info given we can replace in formula (1) like this:

$z=\frac{(33-31)-0}{\sqrt{\frac{8^2}{330}+\frac{7^2}{310}}}}=3.37$

P value

Since is a one right tailed test the p value would be:

$p_v =P(Z>3.37)=1-P(Z$

Comparing the p value with a significance level for example $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and we can say that the mean for the Campus 1 is significantly higher than the mean for the group 2.

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Step-by-step explanation:

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Sn = (ar^n - 1)/(r - 1)

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From the information given,

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2) Plan Z: Increase production by 300 vehicles every year. It means that the rate of production is in geometric progression. The formula for determining the sum of n terms of an arithmetic sequence is expressed as

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Where

n represents the number of terms in the arithmetic sequence.

d represents the common difference of the terms in the arithmetic sequence.

a represents the first term of the arithmetic sequence.

From the information given,

n = 4 years

a = 10000

d = 300

Therefore, the sum of the first 4 terms, S4 would be

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S4 = 2[20000 + (3)300]

S4 = 2 × 20900

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2 years ago

Paco's cell phone carrier charges him $0.20 for each text message he sends or receives, $0.15 per minute for calls, and a $15 mo

Katarina [22]

Given:

Paco's cell phone carrier charges him $0.20 for each text message he sends or receives, $0.15 per minute for calls, and a $15 monthly service fee. Paco is trying to keep his bill for the month below $30.

To Find:

The number of texts 't' Paco can send/receive in a month.

Answer:

$0\leq t$

best describes the number of texts he can send or receive to keep his bill less than $30 in a month.

Step-by-step explanation:

Paco wants to keep is monthly bill below $30.

We see that he has to pay a foxed monthly service fee of $15. This means he is only left with a limit of $30 - $15 = $15 for his monthly calls and texts.

That is, the amount he has to pay for texting and calling has to be less than $15.

For texts, the cell phone carrier charges $0.20 for sending/receiving texts.

For calls, he is charged $0.15 per minute.

Let the number of text messages Paco can send or receive in a month be denoted by 't'.

Let the number of minutes Paco can call in a month be denoted by 'c'.

Then, the total cost of text messages he can send or receive per month would be 0.20t and the total cost of the minutes he spends on calls would be 0.15c. Together, the sum of these has to be less than $15 if his monthly bill has to be kept less than $30 (accounting for the monthly service fee).

So,

$0.20t+0.15c$

The number of texts he can send will dpend on the number of minutes he spends on his calls. For Paco to spend maximum number of texts, he has to spend 0 minutes on calls.

So, putting c = 0, the aboce equation can be written as

$0.20t+0$

That is, Paco has to send and receive less than 75 texts.

So,

$0\leq t$

best describes the number of texts he can send or receive to keep his bill less than $30 in a month.

3 0

2 years ago

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