Answer:
Given that,
(a) Government purchases increases by $80,000
Marginal propensity to consume (MPC) = 0.75


= 4 × 80,000
= $320,000
Therefore, Real GDP increases by $320,000.
(b) If transfers increases by $80,000
MPC = 0.75 (MPC doesn't change)


= 3 × 80,000
= $240,000
Therefore, total change in real GDP is $240,000. So, real GDP increases by $240,000.
(c) It is totally clear from the above calculations that an increase in the government transfers or taxes, as opposed to an increase in government purchases will result in a smaller eventual effect on real GDP.
Change in real GDP occur due to increase in government transfers = $240,000
Change in real GDP occur due to increase in government purchases = $320,000