Maya and Max are neighbours. Both grow lettuce and tomatoes in their gardens. Maya can grow 40 heads of lettuce or 8 kilograms of tomatoes this summer. Max can grow 42 heads of lettuce or 6 kilos of tomatoes this summer.

If Maya and Max specialize and trade, the price of 1 kilo of tomatoes (in terms of lettuce) would be between

• 5 and 6
• 6 and 8
• 5 and 7
• 4 and 7

heads of lettuce.