1. An 8 pound bag of potatoes costs $18. At this price how much would 15 pounds of potatoes cost?
2. Sarah can fit 115 books in 2 bookcases. At that rate, how many bookcases does she need to hold 360 books?
3. Jeremy and Caitlyn collect baseball cards. The ratio of Jeremy's cards to Caitlyn's cards is 9 to 3. After Jeremy gave Caitlyn 12 cards, they had an equal amount of cards. How many cards did Caitlyn and Jeremy have at first? Explain.