Benefit and Marginal Benefit

For now, though, we shall assume that the Economian economic planning bureau knows how to measure benefits, can express them in units of food, and that the total benefits from production of machines in Economia are as shown in Table 3.

Table 3. Total Benefit of Machine Production

machines	benefits
0	0
100	220
200	420
300	600
400	760
500	900
600	1020
700	1120
800	1200
900	1260
1000	1300

As before, though, the total benefit from machine production does not tell us the whole story. We will want to look at the marginal benefit, which is defined similarly as marginal cost. the marginal benefit of machine production is the benefit from producing just one more machine. Once again, we cannot compute the marginal benefit directly from the data in Table 3. Instead we approximate it, using the formula

very much as we did for marginal cost. Accordingly, going from 400 to 500 machines, we have machines = 100, benefits = 900-760 = 140, and the marginal benefit in this range is approximately 1.4 units of food per machine.