1.is MPC and MPS are always constant....why they do not change with change in income??
2.why APC falls at a rate less than that of MPC or why MPC rises at a rate greater than APC??
1) MPC refers to the ratio of change in the consumption expenditure and change in the disposable income. Algebraically,
Now, when we say MPC is constant, it implies that the ratio of change in consumption expenditure to the change in disposable income is constant. This is because a consumer tends to consume a fixed proportion of his income unless his income changes to a very large extent (which is not applicable in most cases) . The same concept is applicable in case of marginal propensity to save.
2) A similar question has already been answered by our expert. Follow the given link to view the same.
https://www.meritnation.com/ask-answer/question/1-why-change-in-consumption-can-never-be-more-than-change-in/economics/6833629