a round trip car ride took 12 hours. the first half of the trip took 7 hours at a rate of 45 miles per hour. what was the average rate of speed on the return trip?

Distance = rate * time

The distance in both directions are equal.

rate1 * time1 = rate2 * time2

550

63 mph

To determine the average rate of speed on the return trip, we need to first calculate the total time taken for the return trip.

We know that the entire round trip took 12 hours, and the first half of the trip took 7 hours. Therefore, the return trip must have taken 12 - 7 = 5 hours.

Next, we'll calculate the total distance covered in the round trip. Since the first half of the trip was 7 hours at a rate of 45 miles per hour, the distance covered in that portion is 7 * 45 = 315 miles.

Since the round trip covers the same distance going and returning, the total distance traveled is 2 * 315 = 630 miles.

Finally, to find the average rate of speed on the return trip, we divide the total distance (630 miles) by the time taken for the return trip (5 hours).

Therefore, the average rate of speed on the return trip is 630 / 5 = 126 miles per hour.