Aubree drives 15 miles in 20 minutes. If she drove three hours in total at the same rate, how far did she go

Ijust need these 2 questions answered (the second pic is just confirmation i'm not confident in that answer)

It takes an ant farm 3 days to consume 1/2 of an apple. at that rate, in how many days will the ant farm consume 3 apples

While on a train trip, marsha noticed that there were 35 people in her train car. after the next stop, there were only 21 people in her car. if p represents the percent decrease in the number of people in marsha's train car, what is p?