(5 pts) It takes Jack 3 hours longer to write holiday cards than it takes Jill. Together, they can write them
in 2 hours. How long does it take each person to write the cards working alone?​

Answer:

Jack needs 6 hours and Jill needs 3 hours.

Step-by-step explanation:

Let's define the variables:

X  = rate at which Jack can write a holiday card.

Y = rate at which Jill can write a holiday card.

Each of them will need a given time to write a card, such that:

X*T = 1 card

We know that Jack needs 3 more hours to write a card than Jill, then Jill needs 3 hours less than Jack, so if Jack needs T hours, Jill will need T - 3 hours

Then we have the equation:

Y*(T - 3 hr) = 1 card

And we also know that when they work together, they need 2 hours, then:

(X + Y)*2 hr = 1 card.

So we have 3 equations:

X*T = 1 card

Y*(T - 3 hr) = 1 card

(X + Y)*2 hr = 1 card.

Now let's ignore the card part just for the equations, then we get:

X*T = 1

Y*(T - 3 hr) = 1

(X + Y)*2 hr = 1

To solve it, we first need to isolate one variable in one of the equations, let's isolate T in the first equation, we get:

T = 1/X

Now we can replace this in the second equation to get:

Y*((1/X) - 3hr) = 1

So now we have two equations:

(X + Y)*2 hr = 1

Y*((1/X) - 3hr) = 1

We need to do the same, isolate one variable in one of the equations, let's isolate Y in the above one:

Y*2hr = 1 - X*2hr

Y = (1 - X*2hr)/2hr

Now we can replace this in the other equation to get:

((1 - X)/2hr)*((1/X) - 3hr) = 1

Now we can solve this for X:

((1 - X)/2hr)*((1/X) - 3hr) = 1

(1 - X)*((1/X) - 3hr) = 2 hr

1/X - 3hr - X*2hr/X + X*2hr*3hr = 2hr

1/X - 3hr - 2hr + X*6hr^2 = 2hr

1/X + X*6hr^2 = 2hr + 3 hr + 2 hr = 7hr

1/X + X*6hr^2 = 7hr

Now we can multiply all by X to get:

X/X + X*(X*6hr^2) = 7hr*X

Now we have the quadratic equation:

(6hr^2)*X^2 - (7hr)*X + 1 = 0

We can find the solutions of this equation if we use the Bhaskara's formula, the solutions are:

[tex]X = \frac{-(-7hr) +- \sqrt{(-7hr)^2 - 4*(6hr^2)*1} }{2*6hr^2} = \frac{7hr +- 5hr}{12 hr^2}[/tex]

Then we have two solutions:

X = (7hr + 5hr)/12hr = 1 hr^-1

And this is the rate at which Jack writes a card, so the actual units are:

X =  0.167 card/hr

Then Jill's rate will be:

Y = (1 - X*2hr)/2hr = (1 - 1card/hr*2hr)/2hr = -0.5 card/hr

So we have a negative rate, this makes no sense, so we can discard this option. The other solution for X is:

X = (7hr - 5hr)/12hr = 0.166... hr^-1

And this is the rate at which Jack writes a card, so the actual units are:

X =  0.166... card/hr

If we have this, then the rate for Jill will be:

Y = Y = (1 - X*2hr)/2hr = (1 - 0.167card/hr*2hr)/2hr = 0.333 card/hr

Then we have:

X = 0.167 card/hr

If we use the first equation, we get:

(0.166... card/hr)*T = 1 card

T = 1 card/((0.166... card/hr)) =  6 hours

Then Jack needs 6 hours to write a card.

And we know that Jill needs 3 hours less than that, then Jill needs 3 hours.

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B.) A $12,500 debit to salaries expense in a journal entry was incorrectly posted to the ledger as a $12,500 credit, leaving the salaries expense account with a $2,350 debit balance.

C.) A $6,250 credit to consulting fees earned (revenues) in a journal entry was incorrectly posted to the ledger as a $6,250 debit, leaving the consulting fees earned account with a $14,300 credit balance.

D.) A $6,250 debit posting to accounts receivable was posted mistakenly to land.

E.) A $12,500 debit posting to equipment was posted mistakenly to cash.

F.) An entry debiting cash and crediting accounts payable for $12,500 was mistakenly not posted.


Please answer which one is it. Thank you!

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g(x) = _______
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Check all of the boxes that apply.

The vertex is (1, -9).

The graph opens upward.

The graph is obtained by shifting the graph of f(x) = 6(x + 1)2 up 9 units.

The graph is steeper than the graph of f(x) = x2.

The graph is the same as the graph of f(x) = 6x2 + 12x - 3.

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IM GIVING 40 POINTS !! DONT SKIP :((.

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B.
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The variables
(select)
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The greater police officers' median salary corresponds to a
(select)
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(select)
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Causation is
(select)
but it is unknown which variable causes the other. A greater median salary of police officers could cause a greater number of violent crimes per 1,000 people or a greater number of violent crimes per 1,000 people could cause a greater median salary of police officers. It is also possible that another factor causes a greater median salary and a greater number of violent crimes per 1,000 people.

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Find the value of the F-test statistic for testing whether the average gas mileage is the same for the four car models. Round your answer to two decimal places, if necessary.

Car A Car B Car C Car D
Driver 1 23 39 22 25
Driver 2 37 39 28 39
Driver 3 39 40 21 25
Driver 4 34 36 27 33
Driver 5 27 35 26 37

Required:
Make the decision to reject or fail to reject the null hypothesis that there is no difference in the average gas mileages of the four car models. State the conclusion in terms of the original problem. Use alpha = 0.01.

a. We reject the null hypothesis. At the 0.01 level of significance, there is sufficient evidence of a difference in average gas mileages of the four car models.
b. We fail to reject the null hypothesis. At the 0.01 level of significance, there is not sufficient evidence of a difference in average gas mileages of the four car models.
c. We fail to reject the null hypothesis. At the 0.01 level of significance, there is sufficient evidence of a difference in average gas mileages of the four car models.
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