(a) Marginal propensity to consume (MPC) = 0.7
(b) Multiplier of this economy:
= 3.33
(c) Decrease government purchases by $300 billion,
Initial change in consumption = Change in government purchases × MPC
= $300 × 0.7
= -$210 billion
(d) This decreases income yet again, causing a second change in consumption equal to:
= Initial change in consumption × MPC
= -$210 × 0.7
= -$147 billion
(e) The total change in demand resulting from the initial change in government spending is:
= Change in government purchases × Multiplier
= $300 × 3.33
= -$1 trillion