The distance between A and B is 600 kilometers. A bus travels from A to B at a speed of 60 kilometers per hour, and a train travels from B to A at a speed of 50 kilometers per hour. The bus departs at 8:00 a.m. If the two buses meet at the midpoint, the truck must depart at what o'clock in the morning.
甲乙两地相距600千米，客车以每小时60千米的速度由甲地开往乙地，火车以每小时50千米的速度由乙地开往甲地．上午8时客车出发，要使两车在中点相遇，货车必须在上午多少点出发．
<gadget id="calculator">600 / 2 / 50</gadget>
<output>6</output>

<gadget id="calculator">600 / 2 / 60</gadget>
<output>5</output>

<gadget id="calculator">6 - 5</gadget>
<output>1</output>

<gadget id="calculator">8 - 1</gadget>
<output>7</output>

<result>7</result>