Answer:
1 hour 39 Minutes
Explanation:
At 8:09 P.M
Only the first plane was in the air
At 9:14 P.M
Both Planes were in the air
At 10:53 PM
First plane lands
For how long were both planes in the air at the same time.
Both planes were in the air between the 9:14 P.M and 10:53 PM
Duration = 1 hour 39 Minutes