The ratio of the walking speed of A and B is 7:5, and A and B start from A and B at the same time respectively. If they are going in the same direction and meet after 0.5 hours, if they are going in the same direction, how long will it take for A to catch up with B?
甲、乙两人步行速度之比是7：5，甲、乙分别从A、B两地同时出发．如果相向而行，0.5小时后相遇，如果他们同向而行，那么甲追上乙需要多长时间？
<gadget id="calculator">7 + 5</gadget>
<output>12</output>

<gadget id="calculator">7 - 5</gadget>
<output>2</output>

<gadget id="calculator">0.5 / 2</gadget>
<output>0.25</output>

<gadget id="calculator">12 * 0.25</gadget>
<output>3</output>

<result>3</result>