I think you have thongs backwards. Since you can set the price at will, it should be the independent variable. So, your points should be
(90,200) and (40,1200)
That makes the slope of the line (1200-200)/(90-40) = 20
So, the equation is
y-200 = 20(x-90)
y - 20x - 1600
Other than that, you did good work :-)
The quantity demanded for a certain brand of MP3 players is 200 units when the price is set at $90. The quantity demanded is 1,200 units when the unit is $40. Find the demand equation.
For this problem, I set the points as (demand quantity, price). So my points were (200,90) and (1200,40). I then proceeded to look for slope m.
m= 40-90/1200-200 = -50/1000 =-1/20
Then used point-slope (I plugged in the points from (200,90)):
y-90= -1/20 (x-200)
y-90+90= -1/20x+10+90
y=-1/2-x+100 as my final answer.
I need someone to check my work.
1 answer
1 answer