You take 2.16 hours and 88.64 miles and set it up in a fraction; 88.64/2.16 which equates to ~44.04 or 44.037037037(repeating) to be specific, but lets round it to 44.04. You then know that your travel 44.04 miles an hour, so you take 257.96 and divide it by 44.04 to get your answer 5.87402361(etc.) which we'll equate to 5.9 hours as your final answer. I don't know what context this problem would be in because they wouldn't put decimals in this type of problem.