A recipe uses 2 cups sugar for every 3 cups flour. If there are 18 cups flour, how many cups sugar are needed?
On a trip there are 4 teachers for every 9 students. If 36 students attend, how many teachers join?
Paint is mixed 7 red cans to 2 blue cans. If 14 red cans are used, how many blue cans are needed?
The library buys 5 fiction for every 8 nonfiction books. If 65 books are bought total, how many are nonfiction?