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1 year ago

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Stephanie has a $40 balance on her credit card. She makes two additional charges to pay $20 for gas and $25 for parking. Then sh

e makes a credit card payment of $30.
What is her remaining balance?

2 answers:

nikdorinn [45]1 year ago

7 0

Answer:

She should have $25 left

Step-by-step explanation:

It she has a total of $40 and you take away the $20 she spent of gas and the $25 she spent for parking she would have -$5 but since she paid $30 back on the card she has a balance of $25

77julia77 [94]1 year ago

3 0

She should have a balance of 25

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A study was recently conducted at a major university to estimate the difference in the proportion of business school graduates w

sveta [45]

Answer:

$(0.1875-0.274) - 1.96 \sqrt{\frac{0.1875(1-0.1875)}{400} +\frac{0.274(1-0.274)}{500}}=-0.1412$

$(0.1875-0.274) + 1.96 \sqrt{\frac{0.1875(1-0.1875)}{400} +\frac{0.274(1-0.274)}{500}}=-0.0318$

And the 95% confidence interval would be given (-0.1412;-0.0318).

We are confident at 95% that the difference between the two proportions is between $-0.1412 \leq p_A -p_B \leq -0.0318$

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".

$p_A$ represent the real population proportion for business

$\hat p_A =\frac{75}{400}=0.1875$ represent the estimated proportion for Business

$n_A=400$ is the sample size required for Business

$p_B$ represent the real population proportion for non Business

$\hat p_B =\frac{137}{500}=0.274$ represent the estimated proportion for non Business

$n_B=500$ is the sample size required for non Business

$z$ represent the critical value for the margin of error

The population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{p(1-p)}{n}})$

Solution to the problem

The confidence interval for the difference of two proportions would be given by this formula

$(\hat p_A -\hat p_B) \pm z_{\alpha/2} \sqrt{\frac{\hat p_A(1-\hat p_A)}{n_A} +\frac{\hat p_B (1-\hat p_B)}{n_B}}$

For the 95% confidence interval the value of $\alpha=1-0.95=0.05$ and $\alpha/2=0.025$ , with that value we can find the quantile required for the interval in the normal standard distribution.

$z_{\alpha/2}=1.96$

And replacing into the confidence interval formula we got:

$(0.1875-0.274) - 1.96 \sqrt{\frac{0.1875(1-0.1875)}{400} +\frac{0.274(1-0.274)}{500}}=-0.1412$

$(0.1875-0.274) + 1.96 \sqrt{\frac{0.1875(1-0.1875)}{400} +\frac{0.274(1-0.274)}{500}}=-0.0318$

And the 95% confidence interval would be given (-0.1412;-0.0318).

We are confident at 95% that the difference between the two proportions is between $-0.1412 \leq p_A -p_B \leq -0.0318$

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1 year ago

At the time of her grandson's birth, a grandmother deposits $ 2000 in an account that pays 3.5 % compounded monthly. What will

11Alexandr11 [23.1K]

At the time of her grandson's birth, a grandmother deposits $12,000.00 in an account that pays 2% compound monthly. What will be that value of the account at the child's twenty-first birthday, assuming that no other deposits or withdrawls are made during the period.
---
A(t) = P(1+(r/n))^(nt)
---
A(21) = 12000(1+(0.02/12))^(12*21)
---
A(21) = 12000(1.5214)
---
A(21) = #18,257.15

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2 years ago

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A fair coin is flipped twice. Drag letters to complete the tree diagram to represent the sample space

ankoles [38]

Answer:

Step-by-step explanation:

HH

HT

TH

TT

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2 years ago

Sal was tired of waiting for Amir to show up at their meeting place, so he started running at an average speed of 4.5 mph withou

skelet666 [1.2K]

Let s and a represent the position of Sal and Amir respectively.

s=.75+4.5t and a=-.25+6.7t

When Sal catches Amir, s=a so we can say.

-.25+6.7t=.75+4.5t subtract 4.5t from both sides

-.25+2.2t=.75 add .25 to both sides

2.2t=1 divide both sides by 2.2

t=5/11 hours

t≈0.45 hours (to nearest hundredth of an hour)

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2 years ago

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Mr. Smith had 33 dozen cans. He sold 340 of them at 15$ each. He sold the remaining cans at a discount of 20% each. How much mon

iren2701 [21]

Answer:

Mr. Smith collects $5748 from selling the can.

Step-by-step explanation:

Given total number of cans = $33\times12=396$

Selling price of one can = $15.

$\therefore \textrm{Selling price of 340 cans} = \textrm {selling price of one can} \times \textrm {number of cans}=15\times340=\$5100$

Now remaining number of cans = total number of cans - sold number of cans = $396-340=54$

For remaining number of cans he gives a discount of 20% each,

∴ Selling price of one can = $15-\frac{15\times20}{100}=15-3=12$

∴ Selling price of 54 cans = $\textrm{selling price of one can} \times \textrm{number of cans}=12\times54=\$648$

So total money he earns = $\$5100+\$648= \$5748$ .

Thus Mr. Smith earns $5748 by selling the cans.

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2 years ago