SOLUTION: I have a problem that is confusing me....the relationship between the number of "D" of dog licenses issued by the city of Denver and it's population "P" can be modeled with a Linea

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: I have a problem that is confusing me....the relationship between the number of "D" of dog licenses issued by the city of Denver and it's population "P" can be modeled with a Linea      Log On


   



Question 763262: I have a problem that is confusing me....the relationship between the number of "D" of dog licenses issued by the city of Denver and it's population "P" can be modeled with a Linear Equation. When the Population was 20,000, the number of licenses issued was 2500. The Rate of increase in the number of licenses issued is 11 for every 200 new residents.
1) find a linear equation that models the relationship between the number of "D" of dog licenses and it's population "P".
2)What is the value of the vertical-intercept? What are the units? What is it's significance?
I am thoroughly stuck. Help me please!

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
They are saying that the ratio +D%2FP+=+11%2F200+ is
the linear rate that +D+ is increasing
-----------------
Plot +D+ on the vertical axis and
plot +P+ on the horizontal axis
-----------------------------
Using this plan, you are given the point ( 20000, 2500 )
Now you can write the general point-slope formula:
+%28+D+-+2500+%29+%2F+%28+P+-+20000+%29+=+11%2F200+
Multiply both sides by +200%2A%28+P+-+20000+%29+
+200%2A%28+D+-+2500+%29+=+11%2A%28+P+-+20000+%29+
+200D+-+500000+=+11P+-+220000+
+200D+=+11P+%2B+280000+
+D+=+%28+11%2F200+%29%2AP+%2B+1400+
--------------------------
The vertical intercept is at +P+=+0+ and
+D+=+1400+
--------------------------
This says that when there were no people, they still
issued dog licenses
I think what this says is that there were more dogs than people
until +P+=+D+ when the population caught up with the number of dogs
If I say +P+=+D+ then,
+P+=+%28+11%2F200+%29%2AP+%2B+1400+
+P%2A%28+200%2F200+-+11%2F200+%29+=+1400+
+%28+189%2F200+%29%2AP+=+1400+
+P+=+%28+200%2F189+%29%2A1400+
+P+=+1481+ is when dog licenses issued
equals population