1a) Look for the interception of the graph with the line x=12. Therefore, the answer is approximately 36 ounces.
1b) Look for the intersection between the graph and the line y=16. Thus, the answer is 24 days.
3) Look for the point on the graph whose x-coordinate is equal to zero. The answer is that the bag weighed 56 ounces before it was opened.
4) We need to find a point on the graph such that its y-coordinate is equal to zero; therefore, the answer is between 32 and 36 days (the scale of the graph is not enough to give a more accurate answer). The answer is likely to be 33 days.