A bus departs from City A to City B. It departs at 9:00 am and travels 60% of the journey until 12:30 noon. At this time, it is still 70 kilometers away from City B. What is the speed of the bus?
一辆客车从甲城开往乙城，上午9点出发，到中午12点30分行了全程的60%，这时离乙城还有70千米，求客车的速度？
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">70 / (2/5)</gadget>
<output>175</output>

<gadget id="calculator">175 * (3/5)</gadget>
<output>105</output>

<gadget id="calculator">105 / 3.5</gadget>
<output>30</output>

<result>30</result>