The Marginal Propensity to Consume (MPC) is the additional amount consumed as a fraction of additional disposable income.
Initial income = N150.
New income = N250.
Change in income = N250 – N150 = 100
Initial consumption = N100
New consumption = N150.
Change in consumption = N150 - N100 = N50.
MPC = Change in consumption ÷ Change in income .
= 50/100 = ½
MPC = 0.5