Megan walked a total of 4 kilometers by making 2 trips to school. How many trips will Megan have to make in all to walk a total of 18 kilometers? Assume the relationship is directly proportional.

Ron jarred 12 liters of jam after 4 days. How many days does Ron need to spend making jam if he wants to jar 18 liters of jam in all? Assume the relationship is directly proportional.

Spencer took a total of 8 quizzes over the course of 2 weeks. How many weeks of school will Spencer have to attend this quarter before he will have taken a total of 12 quizzes? Assume the relationship is directly proportional.

Isabelle bought 6 souvenirs during 2 days of vacation. How many days will Isabelle have to spend on vacation before she will have bought a total of 9 souvenirs? Assume the relationship is directly proportional.