Final answer:
John's average speed for the whole journey is 54 miles per hour. This was calculated by finding the total distance he drove, which was 270 miles, and dividing it by the total time spent, which was 5 hours.
Step-by-step explanation:
To find John's average speed for the whole journey, we'll need to calculate the total distance he traveled and the total time he spent traveling. John drove 3 hours at 50 miles per hour and 2 hours at 60 miles per hour. To find the distance for each part of the trip, we multiply the time by the speed. Thus, for the first part of the journey, he drove 3 hours × 50 miles/hour = 150 miles. For the second part, he drove 2 hours × 60 miles/hour = 120 miles.
The total distance traveled is 150 miles + 120 miles = 270 miles. The total time spent driving is 3 hours + 2 hours = 5 hours.
Finally, to find John's average speed, we use the formula:
Average speed = Total distance / Total time = 270 miles / 5 hours = 54 miles per hour.
Hence, John's average speed for the whole journey is 54 miles per hour.