To determine the distance between them after walking for 2.5 minutes, you will need to calculate how far they will walk in that time.
You can use the distance formula: d = rt, where d is the distance, r is the rate, and t is the time.
d = 80 ft/min x 2.5 min
d = 200 ft for each of them
1600 - 200 - 200 = 1200 feet
They are 1200 feet away from each other.