How to find the midpoint of CD

Haruka hiked several kilometers in the morning. she hiked only 66 kilometers in the afternoon, which was 25% less than she had hiked in the morning. how many kilometers did haruka hike in all?

You have 12 balloons to blow up for your birthday party. you blow up 1/3, and your friend blows up 5 of them. what fraction of the baloons still need blowing up

Anew movie is released each year for 14 years to go along with a popular book series. each movie is 2 minutes longer than the last to go along with a plot twist. the first movie is 70 minutes long. use an arithmetic series formula to determine the total length of all 14 movies