Suppose life expectancy in years (l) is a function of two inputs, health expenditures (h) and nutrition expenditures (n) in hundreds of dollars per year. the production function is

Based on this assumption, the production function is:
L= f(H,N) 
This means that Life expectancy is dependent on (H) Health expenditures and (N) Nutrition expenditures. 
In microeconomics, this function creates a correlation between increased health spending and good nutrition on increased life expectancy.

They use the si unit, or metric system its all the same thing