Assuming change was linear, write equation in slope-intercep

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dbospj
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Assuming change was linear, write equation in slope-intercep

Postby dbospj » Mon Sep 24, 2012 2:12 pm

Hello everyone. I need help with the following problem. If anyone can give step by step details & a solution, I will be greatly appreciative. Thank you http://www.purplemath.com/learning/posting.php?mode=post&f=8#

1.) In 2000 a small farm had sales of $176,000.00. In 2010, the same farm had sales of $301,000.00.

(a) Assuming that the change was linear, write the equation(in Slope-Intercept Form) of the relationship where y is the sales (in thousands of dollars) and x is the time in years. Hint: It is better to consider 2000 as "year 0"(year zero) and write the first ordered pair as (0, 176) where the "176" is the sales in thousands of dollars.

(b) What exactly does the slope tell you about the rate of change in sales PER YEAR?

(c) Use your equation to predict the sales for the farm in the year 2015.

(d) Use your equation to estimate the year that sales for the farm will reach $500,000..

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maggiemagnet
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Re: Assuming change was linear, write equation in slope-inte

Postby maggiemagnet » Tue Sep 25, 2012 12:36 am

dbospj wrote:1.) In 2000 a small farm had sales of $176,000.00. In 2010, the same farm had sales of $301,000.00.

(a) Assuming that the change was linear, write the equation(in Slope-Intercept Form) of the relationship where y is the sales (in thousands of dollars) and x is the time in years. Hint: It is better to consider 2000 as "year 0"(year zero) and write the first ordered pair as (0, 176) where the "176" is the sales in thousands of dollars.

Can you follow the hint and find two points and then find the slope from there? (To review how to find the slope for two points, try here.)
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dbospj
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Re: Assuming change was linear, write equation in slope-inte

Postby dbospj » Tue Sep 25, 2012 1:10 am

Thank you for the link. I figure it out ( I think) up to C.
The slope is 125/10.
B) I figured the sales per year increases because it's steeper than the identity line?
C) I think the 2015 predicted sale amount would be $488,500.00?
D) I'm not sure how to write an equation for this?

Any help would be greatly appreciated.
Thanks

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maggiemagnet
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Re: Assuming change was linear, write equation in slope-inte

Postby maggiemagnet » Tue Sep 25, 2012 8:26 pm

dbospj wrote:Thank you for the link. I figure it out ( I think) up to C.
The slope is 125/10.

You can reduce this to m = 12.5 (or at least make a fraction of 25/2).

dbospj wrote:B) I figured the sales per year increases because it's steeper than the identity line?

I think they're wanting you to see that m is positive so this means "increasing".

dbospj wrote:C) I think the 2015 predicted sale amount would be $488,500.00?

How did you get this?

dbospj wrote:D) I'm not sure how to write an equation for this?

You can see how to get the equation from the points by looking here.
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dbospj
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Re: Assuming change was linear, write equation in slope-inte

Postby dbospj » Tue Sep 25, 2012 10:08 pm

Oh yeah I forgot to reduce. Is $488,500.00 not right? I couldn't find a way on how to write the equation from the link. If no one wants to help with the problem, can someone maybe give an example of how to solve a similar problem, something like when will $600,000 be reached?

dbospj
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Re: Assuming change was linear, write equation in slope-inte

Postby dbospj » Tue Sep 25, 2012 10:28 pm

Oh I used the wrong number in the equation for C. The predicted sale amount would be $ 363,500.

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maggiemagnet
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Re: Assuming change was linear, write equation in slope-inte

Postby maggiemagnet » Wed Sep 26, 2012 11:33 am

dbospj wrote:Oh I used the wrong number in the equation for C. The predicted sale amount would be $ 363,500.

Yep!
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