The scatterplot below shows a relationship between the time spent learning a piece of music for the guitar in the score for the annual solo competition, predict the score for 15 weeks
Of practice
Unfortunately, I cannot see the scatterplot you are referring to. However, in general, if you have a scatterplot with a line of best fit that represents the relationship between two variables (in this case, the time spent learning a piece of music and the score for the competition), you can use that line to make a prediction.
Let's say that the line of best fit for this scatterplot has an equation of y = 3x + 12 (where y is the score and x is the time spent practicing in weeks). To predict the score for 15 weeks of practice, you would plug in x = 15 and solve for y:
y = 3(15) + 12
y = 45 + 12
y = 57
So based on this scatterplot (and assuming the line of best fit is accurate), a person who practices for 15 weeks would be predicted to score 57 in the competition.