Two cars, A and B, start from A at the same time, and drive back and forth between A and B, which are 60 kilometers apart. It is known that the speed of A and B is 30 kilometers per hour, and the speed of B is 20 kilometers per hour. m, how long will it take for cars A and B to meet head-to-head for the fifth time?
甲、乙两车同时从A地出发，在相距60千米的A、B两地之间不断往返行驶，已知甲车的速度是每小时30千米，乙车的速度是每小时20千米，则多长时间后甲乙两车第五次迎面相遇？
<gadget id="calculator">2 * 5</gadget>
<output>10</output>

<gadget id="calculator">30 + 20</gadget>
<output>50</output>

<gadget id="calculator">10 / 50</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">60 * (1/5)</gadget>
<output>12</output>

<result>12</result>