text: import numpy as np
  
  
  def calc_prod(coal, oil, elec):
      rates = np.array([[0.9, -0.2, -0.2],
                        [-0.4, 0.8, -0.4],
                        [-0.1, -0.2, 0.8]])
      rates_inv = np.linalg.inv(rates)
      production = np.array([coal, oil, elec])
      return np.dot(rates_inv, production)
  
  
  def main():
      prod_coal, prod_oil, prod_electricity = calc_prod(50000, 75000, 100000)
      print("Production: Coal-%.0f, Oil-%.0f, Electricity-%.0f" % (prod_coal, prod_oil, prod_electricity))
  
  
  if __name__ == "__main__":
      main()
  