A local retailer has determined that the number x of PortaBoy game systems sold in a week is related to the price p in dollars of each system

Question

105game systems were sold when the price was $70. When the systems went on sale the following week, 175 systems were sold at $50 a piece.

 

Find a linear function which fits this data. Use the weekly sales x as the independent variable and the price p as the dependent variable.

 

I  found the slope as -2/7x and every time I put in for the B the problem says I am incorrect, so I am just curious as to what I am doing wrong to find the linear function. 

 

Answer 1

(105, 70) (175,50)

 

(50-70)/(175-105) = -20/70 = -2/7 <---- yes, your slope is correct.

 

 However, B is the intercept , not the slope. The slope is M.

 

 y = M x + b

 

 (105, 70)

 

70 = (-2/7)(105) + b

 

70 = -30 + b

 

b = 100

 

y = (-2/7)x + 100