Which expression simplifies 2/5 ? a) (-1//2) b) (-1/10)+(-1/2) c) (-1/10)×(-1/2) d) (-1/10)÷(-1/2)

Lin is writing an equation to model the proportional relationship between y, the total cost in dollars of downloading videos from a website, and x, the number of videos downloaded. she knows that the total cost to download 3 videos was $12. her work to find the equation is shown below. joylin’s work step 1 k= 3/12= 0.25 step 2 y= 0.25x where did joylin make her first error?