Suppose that the level of GDP increased by $100 billion in a private closed economy where the marginal propensity to consume is 0.9. Aggregate expenditures must have increased by

Noah met an old friend at a coffee shop. he jotted down the friend's new phone number, but later that afternoon he could not find it or remember what he had done with it. a couple of days later, noah went back to the coffee shop, and while waiting in line, he suddenly remembered where he had put the phone number. this is an example of: