1. When consumption is more than income than saving is negative or when consumption graph is above to income graph than saving is negative.

            C>Y, than S becomes -S

  1. When consumption becomes equals to income or consumption graph meet to income graph at that time saving is zero.

             C=Y, than S=0

  1. When consumption is less than income or consumption graph is below to income than saving increases and becomes positive.

            C<Y, than S becomes +S

                                       

Relationship between APC and APS

We know that APC = C/Y and APS = S/Y

Y = C + S

Divide both side by Y Y/Y = C/Y + S/Y

1 = C/Y + S/Y

1 = APC + APS

1 - APC = APS

Relationship between MPC and MPS We know that

MPC = dC/dY and MPS = dS/dY

Y = C + S

And, dY= dC+dS Divide both side by dY

dY/dY = dC/dY + dS/dY 1 = dC/dY + dS/dY

1 = MPC + MPS

1 - MPC = MPS