An express train and a slow train run towards each other from A and B at the same time, and after 4 hours, the distance is still 240km. It is known that the express train takes 10 hours to complete the journey, and the speed ratio of the express train to the slow train is 3:2. How many kilometers are there between A and B?
一列快车和一列慢车同时从甲、乙两地相向而行，开出4小时后还相距240km．已知快车行完全程要10小时，快车与慢车的速度比是3：2．甲、乙两地相距多少km？
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(1/10) * (2/3)</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/10) + (1/15)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">4 * (1/6)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 - (2/3)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">240 / (1/3)</gadget>
<output>720</output>

<result>720</result>