Question: If Ken's house is twice as far from Dawn's house as Mary's house along a certain road, and Ken's house is 4 miles away from Dawn's house along this same road, how much distance (in miles) will Ken cover if he goes from his house to Dawn's house, then Mary's, then back to Dawn's before going back to his own house? Think carefully first, then make a decision:
Ken's house is twice as far from Dawn's house as Mary's, so the distance between Ken's and Mary's is half that between Ken's and Dawn's (4 miles) which means the former is (1 / 2) * 4 miles = 2 miles. If Ken goes from his house to Dawn's, he has covered 4 miles. He goes from there to Mary's (2 miles, same as Ken's to Mary's) for a total of 4 + 2 = 6 miles. He goes back to Dawn's (another 2 miles) for a total of 6 + 2 = 8 miles. Then he goes to his own house (4 miles) for a final total of 8 + 4 = 12 miles. So the answer is 12.