As suggested by the "laps per minute", the question is asking how many laps are ran each minute. Laps per minute is synonymous for laps/minutes. Thus, 2 laps in 8 minutes is 0.25 laps per minute.
If the train travels 744 miles in 3 hours then to determine the unit rate the train is traveling per hour you have to divide the miles by the hours, in this case (744 miles)/(3 hours). The final result concludes as 248 miles per hour.
