"The horizontal axis labeled quantity ranges from 0 to 15 in increments of 1. The vertical axis labeled dollar ranges from 0 to 120 in increments of 10. A line labeled M R begins at the point (0, 100) goes down to the right and ends at the point (5, 0). A second line labeled D begins at the point (0, 100) goes down to the right and ends at the point (10, 0). A third line labeled M C begins at the point (2, 20) goes up to the right and ends at the point (6, 100). The line M C intersects the line M R at (3, 40) and the line D at (4, 60)."

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