if maria smith's disposable income increases from $600 to $650 and her level of personal consumption expenditures increases from $480 to $520, you may conclude that her marginal propensity to if maria smith's disposable income increases from $600 to $650 and her level of personal consumption expenditures increases from $480 to $520, you may conclude that her marginal propensity to consume is 0.8. consume is 0.25. save is 0.8. consume is 0.4.