Question

9. A consignment store charges a flat rate plus a percent of the sale price for any items it sells. An item priced at $500 carries a total fee of $120 while an item priced at $800 carries a total fee of $180. Use the point- slope equation to find the total fee for an item priced at $300.​

Answer 1

Answer: The total fee for an item priced at $300 is $80.

Explanation:

We can use the two given points to find the slope (m) and one point to find the y-intercept (b) of the line representing the consignment fee equation.

We know the two points are (500, 120) and (800, 180)

slope (m) = (y2-y1)/(x2-x1) = (180-120)/(800-500) = 60/300 = 0.2

Now we can use one of the point to find y-intercept (b)

120 = 0.2(500) + b

b = 20

Now we can use point-slope equation to find the total fee for an item priced at $300

y - 120 = 0.2(x - 500)

y = 0.2x + 20