In the rich country of Emerald, the average income is
£20,000.
In the poorer, neighbouring country of Flint, the average income
is £16,000.
Charlie lives in Emerald and earns £18,000 a year.
He moves to Flint and says "I've made both countries
richer!"
What does he mean? Think about it
before clicking on the island......

Charlie thinks that the
average income in both countries has increased. Can you convince
yourself that Charlie is right?
What other effects can moves between countries have on the average
incomes?
Describe what is required for moves to:
- increase the average incomes in both
countries
- decrease the average incomes in both
countries
- increase one whilst decreasing the
other
Under what circumstances could a move from Emerald to Flint reduce
the average income in Emerald and double the average income in
Flint?
Under what circumstances could Charlie's move produce other
unexpected results ?