Sam has 18 coins in his pocket that are either quarters or nickels. the total value of these coins is $3.90. let q represent the number of quarters and n represent the number of nickels. the following system of equations represents this situation: q+n=18 0.25q+0.05n=3.90

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?