8. Suppose there are three power-generating plants, each of which has access to 5 different production processes. The table below summarizes the cost of each production process and the corresponding number of tons of smoke emitted each.

Suppose the government decides to impose a tax on each ton of smoke emitted. What would be the lowest tax, in whole dollars, that would reduce emissions to 6 tons per day? (10%)

| Process(smoke/day) | A (4 tons/day) | B (3 tons/day) | C (2 tons/day) | D (1 ton/day) | E (0 ton/day) |
| --- | --- | --- | --- | --- | --- |
| Cost to Firm X ($/day) | $500 | $514 | $530 | $555 | $585 |
| Cost to Firm Y ($/day) | $400 | $420 | $445 | $480 | $520 |
| Cost to Firm Z ($/day) | $300 | $325 | $360 | $400 | $550 |