On a road, it takes 15 hours for car A to complete the journey, and 12 hours for car B to complete the journey. Cars A and B drive toward each other from both ends of the road at the same time. After 3 hours, the distance is still 352 kilometers. How many miles is the road.
一条公路，甲车行完全程需15小时，乙车行完全程需要12小时，甲、乙两车同时从这条公路的两端相向而行，经过3小时后，还相距352千米，这条公路长多少千米．
<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/15) + (1/12)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">(3/20) * 3</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">1 - (9/20)</gadget>
<output>11/20 = around 0.55</output>

<gadget id="calculator">352 / (11/20)</gadget>
<output>640</output>

<result>640</result>