Shira is decorating a room with green and purple balloons. she wants to use 4 green balloons for every 5 purple balloons. how many purple balloons will she need if she uses 20 green balloons? use a double number line to solve.

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?