to get the equation of any straight line, we simply need two points off of it, let's use those two points from the table in the picture below.


For this case we have the following variables:
x: number of free throws that Tessa made
y: total number of free throws
We now write the relationship of free throws.
We have then:

Simplifying the expression we have:


Answer:
The fraction of the free throws that she made is:

Cost Price = $60
Markup = 25% x $60 = 0.25 x 60 = $15
Sales Price after markup = $60 + $15 = $75
Discount = 20% x $75 = 0.2 x 75 = $15
Sales Price after discount = $75 - $15 = $60
Sales Tax = 6% x $60 = 0.06 x 60 = $3.60
Sales Price with Discount after tax = $60 + $3.60 = $63.60
Answer: $63.60