Barbara's goal is to practice piano 20min for every 5min of lesson she takes a 20min lesson this week how many?
She is going to practice piano for 80 minutes. First you want to divide the number of minutes in the lesson by 5 to find how many times 5 minutes goes by in 20 minutes. Next you want to multiply your answer for that, which should be 4, by the amount she wants to practice. So you do 4 x 20, and get 80 minutes total.