Oil is pumped continuously from a well at a rate proportional to the amount of oil left in the well. initially there were 3 million barrels of oil in the well; six years later 1,500,000 barrels remain. answer the following:
1.) at what rate was the amount of oil in the well decreasing when there were 1,800,000 barrels remaining?
2.) when will there be 150,000 barrels remaining?