1 minute = 60 seconds
1 hour = 60 minutes = 60*60 seconds = 3600 seconds
1 hour = 3600 seconds
Multiply both sides by 2.1 to get
1 hour = 3600 seconds
2.1*(1 hour) = 2.1*(3600 seconds)
2.1 hours = 7560 seconds
Now use the formula below
d = r*t
where,
d = distance
r = rate or speed
t = time
In this case,
d = unknown
r = 4 ft per sec
t = 7560 seconds (equivalent to 2.1 hours)
So,
d = r*t
d = 4*7560
d = 30240
The bird can travel 30240 feet. Convert this to miles by dividing the value by 5280 (since 1 mile = 5280 feet)
30240/5280 = 5.727 roughly which rounds to 5.7
Answer: C) 5.7 miles
