Cuilan bought a pen and a "Children's Book", the unit prices were 7.65 yuan and 4.6 yuan respectively, and she paid the salesperson 20 yuan, how much should she get back?
翠兰买了一枝钢笔和一本《儿童读物》，单价分别为7.65元和4.6元，付给售货员20元，应找回多少元？
<result>3.05</result>