Question 257915
round trip distance is 60 miles.


rate * time = distance


to travel 60 miles at 60 miles per hour, you have to take 1 hour for the round trip.


this would make the formula:


60 * 1 = 60 which would be true.


the total time it should take would be 1 hour.


you traveled the first leg at 30 miles per hour.


this means that the formula of rate * time = distance for the first leg becomes:


30 * x = 30.


this means that it took 1 hour to travel 30 miles.


this means that you will never be able to average 60 miles per hour for the round trip.


example:


you traveled 30 miles per hour for the first part of the trip.


that took you 1 hour.


you travel 3000 miles per hour for the return trip.


since rate * time = distance, then the formula becomes:


3000 * x = 30


x = 30/3000 = 3/300 = .01 hours


total time it takes is 1.01 hours.


that's 1 hour for the going leg and .01 hours for the return leg.


average rate for the round trip is based on the formula of rate * time = distance:


x * 1.01 = 60


rate you traveled is 60/1.01 = 59.40594059 miles per hour.


you can approach 60 miles per hour overall but you will never quite make it because your divisor will always be a very small amount greater than 1.


this means that your numerator will always be a very small amount less than 60.