A department store buys 100 shirts at a cost of $1,600 and sells them at a selling price of $20 each. Find the percent markup

Lindsay used two points, (x,y; ) and (+2.82), to find the equation of the line, y = mx + b, that passes through the points. y2-y, first, she used the definition of slope and determined that the value of mis x, - . given this information, which expression must represent the value of b?

Any is very appreciated! (picture is provided below)not sure how to do this at all won't lie

Linda loans her friend $250 with a 5% monthly intrest rate. how much was the whole loan?