John jogs at a speed of 4 miles per hour when he runs alone, but runs at 6 miles per hour when he is being dragged by his 100-pound German Shepherd dog. If John and his dog go on a run together for 30 minutes, and then John runs for an additional 30 minutes by himself, how far will John have traveled? Let's answer step by step:
John runs at 6 miles per hour for 0.5 hours, for a distance of 6 * 0.5 = 3 miles. Then John runs at 4 miles per hour for 0.5 hours, for a distance of 4 * 0.5 = 2 miles. In total, John runs 3 + 2 = 5 miles. The answer: 5.