A car travels in a northward direction for a total distance of 512 km. The car completes this trip in 6 hrs. After resting the driver makes the return trip, the return trip only takes 5.5 hours. What is the average speed of the car over the entire trip?

1024/11.5 = ______ mph

You forgot to include the times he was stopped by the police for greatly exceeding the speed limit.

That's 1024 km/11.5 = ? km/hr which works out to be about 55 mph. No speeding ticket today. :-)

Thanks, DrBob!

I goofed and didn't read carefully.

To find the average speed of the car over the entire trip, we need to calculate the total distance covered by the car and divide it by the total time taken.

Let's start by finding the distance covered in the northward trip. We are given that the car travels a total distance of 512 km in 6 hours. Therefore, the average speed for the northward trip can be calculated as:

Average speed = Distance / Time
Average speed = 512 km / 6 hrs
Average speed = 85.33 km/hr

Next, let's find the distance covered in the return trip. Since the return trip took 5.5 hours, we can calculate the distance using the average speed formula:

Distance = Average speed × Time
Distance = 85.33 km/hr × 5.5 hrs
Distance = 469.15 km

Now, to find the total distance covered over the entire trip, we add the distance of the northward trip and the return trip:

Total distance = Distance of northward trip + Distance of return trip
Total distance = 512 km + 469.15 km
Total distance = 981.15 km

Finally, to find the average speed over the entire trip, we divide the total distance by the total time taken:

Average speed = Total distance / Total time
Average speed = 981.15 km / (6 hrs + 5.5 hrs)
Average speed ≈ 88.28 km/hr

Therefore, the average speed of the car over the entire trip is approximately 88.28 km/hr.