There are 5280 feet in a mile so multiply that by 40 (5280 × 40 = 211,200)
Divide that by the amount of minutes in an hour (211,200 ÷ 60 = 3,520)
Divide that by the amount of seconds in a minute (3,520 ÷ 60 = 58.66)
Your answer is 58.66. I don't think it would be necessary to round to the nearest hundred.