(a) Estimate the value of Aggregate Demand (AD) in an imaginary economy : (i) Autonomous Investment (I_0) = Rs. 100 crore (ii) Marginal Propensity to Save (MPS) = 0.2 (iii) Level of Income (Y) = Rs. 4,000 crore (iv) Autonomous Consumption Expenditure (c̄) = Rs. 50 crore (b) State the meaning of propensity to consume.