Two people, A and B, start running at the same time on both sides of the runway 100 meters apart. A runs 5 meters per second, and B runs 4 meters per second. They run back and forth for 15 minutes. How many times have they met?
甲、乙两人在相距100米的跑道两侧同时起跑，甲每秒跑5米，乙每秒跑4米，往返跑了15分钟，两人共碰面相遇了多少次．
<gadget id="calculator">5 + 4</gadget>
<output>9</output>

<gadget id="calculator">100 / 9</gadget>
<output>100/9 = around 11.111111</output>

<gadget id="calculator">900 - (100/9)</gadget>
<output>8_000/9 = around 888.888889</output>

<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">100 * (2/9)</gadget>
<output>200/9 = around 22.222222</output>

<gadget id="calculator">(8_000/9) / (200/9)</gadget>
<output>40</output>

<gadget id="calculator">40 + 1</gadget>
<output>41</output>

<result>41</result>