Answer:
Round 2 adds =$800
Round 3 adds =$640
Step-by-step explanation:
Marginal propensity to consume is the aggregate increase in spending by a consumer for each additional $ they earn. So a Marginal Propensity to consume of 0.8 means that each consumer in the economy consumes 80% of any additional dollars they earn, while they save 20% which is also the marginal propensity to save that is 0.2
So First round adds $1000
Second round adds $1000 * 0.8 = $800 as people use 80% of $1000
Third round adds $800 * 0.8 =$640 as people use 80% of $800
while the remaining is saved.
Hope that helps.