To start, determine how much a non-college graduate would earn over a 40 year period by multiplying their yearly salary by 40, 30,000*40=120,000. Next, increase it by 30%. Do this by taking 30% of 120k to find out how much more money you would make in comparison to a non-college grad, 120,000*.3=36,000. This means a college grad would make $36,000 more than a non-college grad.