ratio of discounted net benefit to cost

例句：

1. 1. The cost of the new product is 20% higher than the old one.
   新产品的成本比旧产品高20%。
2. 2. The ratio of males to females in this population is about 3:1.
   这个人口中男性与女性的比例大约是3:1。
3. 3. The ratio of sugar to water in a solution is an important factor to consider.
   溶液中糖和水的比例是一个需要考虑的重要因素。