Final answer:
The marginal propensity to save and the marginal propensity to import, coupled with an increase in exports, have implications on the economy that affect consumption, saving, and net exports. An increase in exports generally boosts production and consumption but is partially offset by a higher propensity to import.
Step-by-step explanation:
Given the information provided: the marginal propensity to save (s) is 0.20, the marginal propensity to import (m) is 0.30, and the change in exports (dX) is 140 million dollars, the implications on the economy can be far-reaching. The marginal propensity to save indicates that for every additional dollar received, 20 cents will be saved. Conversely, the marginal propensity to consume (MPC) would be 1 - s, equalling 0.80, meaning that 80 cents of every additional dollar will be spent on domestic consumption.
The marginal propensity to import implies that 30 cents of every dollar spent will go towards imports. With the increase in exports by 140 million dollars, this would likely stimulate domestic production to meet the additional foreign demand. However, with a higher propensity to import, some of this positive effect will be mitigated as some of the spending will leave the domestic economy in the form of imports.
In conclusion, while the increased exports should encourage economic growth and boost consumption, the high marginal propensity to import might reduce the net gain from the exports. The net exports would increase by the amount of the export increase minus the additional imports that the induced additional domestic consumption would bring.