Final answer:
The aggregate level of output demanded when the price level is 120 is equal to 340.
Step-by-step explanation:
To find the aggregate level of output demanded when the price level is 120, we need to substitute the given price level into the aggregate demand equation.
P = 800 - 2Y
Since the price level is 120, we have:
120 = 800 - 2Y
2Y = 800 - 120
2Y = 680
Y = 340
Therefore, the aggregate level of output demanded would be 340.