Explain the following:
Marginal propensity to save (MPS).

Marginal propensity to save (MPS). MPS is the ratio of change in saving (ΔS) to change in income (ΔY). Alternatively, MPS is the part of additional income which is saved. In other words, it is a measure of additional saving as proportion of additional (incremental) income. MPS is worked out by dividing change in saving (ΔS) with the corresponding change in income (ΔY). Symbolically:
MPS = ΔS/ΔY
For instance, in the following table, when national income goes up from र 100 crores to र 200 crores, saving also goes up from zero to र 30 crores. In this case MPS = AS/AY -30/100 = 0.3 or 30%.
The value of MPS lies always between 0 and 1. Its reason is if additional income is entirely consumed then there is no saving making MPS = 0. If entire additional income is saved, then MPS = 1. In short, 0 < MPS < 1.