There is a bus line from A to B, and the journey time is 42 minutes. After arriving at the terminus, the driver will rest for at least 10 minutes, and then the bus will turn around. If there is one bus every 8 minutes (not necessarily at the same time) on both sides of the line A and B, how many buses are needed for this line at least?
由甲地到乙地有一条线路的巴士，全程行驶时间为42分钟，到达总站后，司机至少休息10分钟，巴士就调头行驶．如果这条线路甲、乙两边总站每隔8分钟都发一辆(不必是同一时间)，则这条线路至少需多少辆巴士？
<gadget id="calculator">42 + 10</gadget>
<output>52</output>

<gadget id="calculator">2 / 8</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">52 * (1/4)</gadget>
<output>13</output>

<result>13</result>