The distance between A and B is 3400 meters. A and B are walking towards each other from the two places at the same time. A travels 86 meters per minute, and B travels 84 meters per minute. They have traveled for 15 minutes. How many minutes will they have to meet before they meet?
A、B两地相距3400米，甲、乙两人同时从两地相对而行，甲每分钟行86米，乙每分钟行84米，已经行了15分钟，还要行多少分钟才能相遇？
<gadget id="calculator">86 + 84</gadget>
<output>170</output>

<gadget id="calculator">3_400 / 170</gadget>
<output>20</output>

<gadget id="calculator">20 - 15</gadget>
<output>5</output>

<result>5</result>