There are a lot of information's that are already given in the question. Based on these information's the answer can be deduced.
1 mile = 1609 meters
Then
70 miles = 1609 * 70 meters
= 112630 meters
again
1 hour = 3600 seconds
3 hours = 3600 * 3 seconds
= 10800 seconds
So
Speed = 112630/10800 meters/second
= 10.4 meters per second.
So the falcon was flying at a speed of 10.4 meters per second.
