Working alone, pablo can put up a tent in 12 minutes. his mom can put it up by herself in 4 minutes. how many minutes would they take to put up the tent working together?

Can someone me with this problem i don't understand i need

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?

Which of the following contains a variable?