Equation of a Line

Question

Assuming the selling rule is Linear equation of the price and  from the past sales experiment regrading monthly sales that .

 

30 units were sold when prices at $150,000

50 units were sold when prices at $120,000

 

let x=price of condo in thousandth of dollars 

     y= number of units sold in per month 

 

write the linear equation 

y=mx+b , where m=slope, and b= intercept  

Answer 1

Number of condos sold as a function of price

 

Two points (x,y)

(150000, 30), (120000, 50)

 

slope:  m = (50-30)/(120000-150000) = -20/30000 = -1/1500

 

y = mx + b

y = (-1/1500)x + b

 

Using (150000, 30) as (x, y) solve for b

 

30 = (-1/1500)(150000) + b

30 = -100 + b

b = 130

 

y = (-1/1500)x + 130