Suppose that Eve spends all of her income on avocados and walnuts (she has just learned that it is the perfect diet for her brain). She can just afford 9 avocados and 10 packs of walnuts per week. She could also use her entire income to purchase 3 avocados and 12 packs of walnuts per week. The price of one avocado is CZK 20. How much is Eve's income per week? Please, insert numerical value only.