Distance between A and B is 48 miles. Two men started walking from A and B at the same time towards each other. The person who started from A traveled uniformly with average speed 3 mph. While walking, the other man travels uniformly at 4 mph, but takes a 30-minute rest every other hour. When will they meet each other?
Choose the correct choice from the following options:
A) 18 miles away from A B) 18 miles away from B C) after 6 hours from start D) after 8 hours from start E) after 12 hours from start
Since the question is asking when A and B will meet each other, the answer will be one involving time elapsed.   In such questions, look for the symmetrical situation to find a rough estimate or range. For example, in many work-rate questions, it helps if you figure out the situation in which the rate of both people is the same.   Here the average speed of A (assuming guy who starts from A is A) is 3 mph and distance is 48 miles. So this means that A would take a total of   48/3= 
<gadget id="calculator">  48/3</gadget>
<output>16</output>
16 hours to cover the distance from A to B. So, if B's speed were also 3, both A and B would travel for 8 hours to meet in the middle.   Meanwhile, B will start at 4 mph, but during the next hour (because of his break) he will only travel 2 miles. This pattern will continue: 4, 2, 4, 2... meaning B will end up with an average speed of 3 mph for every two-hour period. Since 8 is even, then B will be traveling at the same average speed as A after 8 hours, and the two men will meet in the middle of A and B.   The correct answer is (after 8 hours from start): after 8 hours from start.
<result>D</result>
Distance between A and B is 48 miles. Two men started walking from A and B at the same time towards each other. The person who started from A traveled uniformly with average speed 3 mph. While walking, the other man travels uniformly at 4 mph, but takes a 30-minute rest every other hour. When will they meet each other?