Final answer:
An initial increase in government purchases increases real GDP by more than the initial increase, as illustrated by a multiplier effect of 2.13 in the provided example, turning $100 of spending into $213 in aggregate expenditure.
Step-by-step explanation:
According to the multiplier effect, an initial increase in government purchases increases real GDP by more than the initial increase in government purchases. This is because the initial spending causes a chain reaction of spending within the economy. In the example provided, an original increase of $100 in government spending leads to a rise in aggregate expenditure by $213. Therefore, in this example, the initial $100 in government spending results in an overall increase in real GDP of $213, as calculated by the multiplier of 2.13 ($213/$100).