Dory is building a wall around her garden. It has taken 45 minutes and she is 75% done. What is the total time that will take her to finish building her wall?

So it's easier to calculate if you figure out how much time it took her to finish 25% of the wall. Since it took her 45 minutes to do 75%, it took her 15 minutes to do 25%. Then you just multiply.

Therefore, it takes her 60 minutes to finish building her wall.