There are three cars driving in the same direction on the highway, the passenger car is in front, the truck is in the middle, and the car is behind. At a certain moment, the truck is at the same distance from the passenger car and the car; after 10 minutes of walking, the car catches up with the truck; after another 5 minutes, the car catches up with the passenger car; how many minutes later, the truck catches up with the passenger car?
公路上同向行驶着三辆汽车，客车在前，货车在中，小轿车在后．在某一时刻，货车与客车、小轿车的距离相等；走了10分钟，小轿车追上了货车；又过了5分钟，小轿车追上了客车，再过多少分钟，货车追上客车？
<gadget id="calculator">2 / 15</gadget>
<output>2/15 = around 0.133333</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(2/15) - (1/10)</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">1 / (1/30)</gadget>
<output>30</output>

<gadget id="calculator">30 - 15</gadget>
<output>15</output>

<result>15</result>