544 is what percent of 640?

Don't know how to find x given these segment lengths

Choose the equation below that represents the line that passes through the point (2, 4) and has a slope of 3. a) y − 4 = 3(x − 2) b) y − 2 = 3(x − 4) c) y + 4 = 3(x + 2) d) y + 2 = 3(x + 4)

Apackage of five erasers cost 0. $.39 at this rate how many how much would 60 erasers cost in dollars and cents