A walks 8 kilometers per hour, B walks 10 kilometers per hour, and they both walk from the same place at the same time. After walking for 15 minutes, B forgot to bring something, returned to the original place to pick up the things and chased after A, asking: How many hours can B catch up with A?
甲每小时走8千米，乙每小时走10千米，两人同时由同地而行．走了15分钟，乙忘带东西，返回原地取了东西再追甲，问：乙再过几小时可以追上甲？
<gadget id="calculator">10 - 8</gadget>
<output>2</output>

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

<gadget id="calculator">8 * 0.25</gadget>
<output>2</output>

<result>2</result>