How many lines are determind by two points

In a class, there are 12 girls. if the ratio of boys to girls is 5: 4 how many boys are there in the class

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?

What is the value of m in the equation 1/2 m - 3/4n=16 when n=8