Jeff takes 20 minutes to jog around the race course one time, and 25 minutes to jog around a second time. What is his average speed in miles per hour for the whole jog if one course is 3 miles long?

To find Jeff ' s average speed , we need to divide the total time it takes him to jog around the course by the distance of the course in miles . \n \n The total time it takes Jeff to jog around the course twice is 2 0 + 2 5 = 4 5 minutes . \n \n The distance of the course is 3 miles , which is equal to 4 . 8 kilom 8 kilom eters ( since 1 mile is equal to 1 . 6 0 9 kilom eters ). \n \n To convert the time to hours , we divide the total time by 6 0 , since there are 6 0 minutes in 1 hour : \n \n 4 5 minutes / 6 0 minutes / hour = 0 . 7 5 hours \n \n To convert the distance to hours , we divide the distance by the speed at which Jeff is travel ing ( which is his average speed in miles per hour ): \n \n 4 . 8 2 8 kilom eters / 2 0 miles / hour = 0 . 2 4 1 hours \n \n To find Jeff ' s average speed in miles per hour , we can use the following formula : \n \n A verage speed = Total distance / Total time \n \n Pl ug ging in the values we found above , we get : \n \n A verage speed = 4 . 8 2 8 kilom eters / 0 . 7 5 hours = 6 . 4 8 kilom eters per hour \n \n There fore , Jeff ' s average speed for the whole jog is 6 . 4 8 miles per hour . </s>