Maya and Max are neighbors. Each grows lettuce and tomatoes in their gardens. Maya can grow 45 heads of lettuce or 9 pounds of tomatoes this summer. Max can grow 42 heads of lettuce or 6 pounds of tomatoes this summer. If Maya and Max specialize and trade, the price of tomatoes (in terms of lettuce) would be as follows: 1 pound of tomatoes would cost between __ and __heads of lettuce.