A bird flies across your backyard at 4.0 feet per second. How many miles can the bird travel in 2.1 hours (rounded to the nearest tenth) ?

A) 2.8 mi

B) 3.2 mi

C) 5.7 mi

D) 9.7 mi

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