We develop an equation for the given situation by first writing the general equation for lines,
y = mx + b
Substituting to this given the values given above,
(1990) 430 = b
(2000) 400 = m(10) + 430
The value of m from the equation in 2000 is -3. Thus, the equation of that relates the variables is,
y = -3x + 430
The first one and the second one are the correct sums
The original gross margin is (2.50 / 1.00) - 1 = (2.5 - 1) = 1.5 = 150%
the cost increases 0.25, is an increase of (0.25 / 1.00) = 25%
in order to keep the same gross margin, you need to increase the sale price by 25%
2.50*1.25 = 3.125
Then the gross margin is (3.125 / 1.25) - 1 = (2.5 - 1) = 1.5 = 150% ( same as original )
Answer:

Step-by-step explanation:
