Final answer:
Tom Hanks' character from Cast Away, was shipwrecked for four years, but the question appears to mix this with 'Robinson Crusoe'. In a two-person economy, such as Robinson and Friday's, the balance of trade would be maintained through a barter system based on their respective skills and needs.
Step-by-step explanation:
Tom Hanks' character in the movie Cast Away was shipwrecked on a desert island for four years before his eventual rescue. However, this scenario seems to be mixed up with the plot of the novel 'Robinson Crusoe' by Daniel Defoe, in which the main character, Robinson, is shipwrecked and eventually meets another character named Friday. In this two-person economy, with Robinson and Friday, the balance of trade would be based on the exchange of goods and services that each person can provide. If Robinson is skilled at fishing and Friday excels at building shelters, they could establish a simple barter system where they exchange fish for shelter improvements.