Cars A and B start from A and B, which are 420 kilometers apart, and drive towards each other at the same time. The speed of car A is 64 kilometers per hour, and the speed of car B is that of car A (7/8). How many hours did it take for the two cars to meet?
汽车甲、乙从相距420千米的A、B两地同时出发相对而行，甲车的速度是每小时64千米，乙车的速度是甲车的(7/8)．两车经过几个小时相遇？
<gadget id="calculator">7 / 8</gadget>
<output>7/8 = around 0.875</output>

<gadget id="calculator">64 * (7/8)</gadget>
<output>56</output>

<gadget id="calculator">64 + 56</gadget>
<output>120</output>

<gadget id="calculator">420 / 120</gadget>
<output>7/2 = around 3.5</output>

<result>7/2 = around 3.5</result>