Caculate the total change in a years GDP:
On March 31, you decide to stop throwing away $50 a month on convenince store nachos. You buy $200 worth of equipment, corn meal, and cheese, and make your own nachos for the rest of the year.
If we assume the year to start on 1st January and end on 31st December, then you have already spent $50 per month for three months adding $50 x 3 = $150 to the year's ...
This solution calculates the total change in a year's GDP.