speed = distance / time. You have not given a speed so it cannot be determined
from 51ft to 61ft
21 miles is exactly 21 miles long or if you prefer 36960 yards long. 21 miles is also 110880 feet long and 1,330,560 inches long.
The Eisenhower Memorial Tunnel is 1.6 miles long...almost two miles long.
The present Cascade Tunnel is 7.79 miles long. The original Cascade Tunnel was 2.63 miles long.
how long does 3 miles take with a car