An economy is based on three sectors, and the corresponding technology matrix is 0.2 0.5 0.4 0.6 0.1 0.9 0.4 0.3 0.8 The total output for the economy is 7000 4000 5000 What is the internal demand for the second sector? Remark: introduce the numerical value of your answer without explanation or calculation in plain text and use the point (.) as the decimal separator