In order to find the equation relating the unit price p and the quantity x, let's use the slope-intercept form of the linear equation:
Where m is the slope and b is the y-intercept.
To find the value of m and b, let's use the ordered pairs (x, p) given in the question.
The given points are (1600, 370) and (5600, 420), so we have:
Subtracting the first equation from the second one, we have:
Therefore the equation is p = 0.0125x + 350.
For a unit price of $470, we have:
The lowest price is given by x = 1 (at least one refrigerator will be marketed), so: