This is attempt 4 for this question to be answered

you sold 15 boxes of paper. you had a goal to sell x. 15 boxes is 20% of my goal. what is x.

provide answer and working explanation.

Set up a proportion. You know that 20%= 20/100 and 15=20%.

15/x= 20/100

Cross multiplication method:
15*100=1500
1500/20=75

x=75

You can also find that the numerator to denominator ratio is 1:5 and find the answer by multiplying the known numerator, 15, by 5 to get 75.

Final 75

Hope i can you!