In an exercise of a unit of the People's Liberation Army, motorcycles travel 60 kilometers per hour, and cars travel 40 kilometers per hour. After the car leaves for 1.5 hours, the motorcycle chases the car along the same road. How many hours does it take to catch up?
解放军某部队在一次演习中，摩托车每小时行60千米，汽车每小时行40千米，汽车出发1.5小时后，摩托车沿同路追赶汽车，需多少小时追上．
<gadget id="calculator">40 * 1.5</gadget>
<output>60</output>

<gadget id="calculator">60 - 40</gadget>
<output>20</output>

<gadget id="calculator">60 / 20</gadget>
<output>3</output>

<result>3</result>