The distance between A and B is 450 kilometers. Two cars start from the two places at the same time and drive towards each other. The speed of car A is twice that of car B. After 3 hours, the two cars meet, how many kilometers per hour is the average speed of car A?
A、B两地相距450千米，两辆汽车同时从两地出发相向而行，甲车的速度是乙车的2倍，经过3小时两车相遇，甲车平均每小时行多少千米．
<gadget id="calculator">360 / 3</gadget>
<output>120</output>

<gadget id="calculator">1 + 2</gadget>
<output>3</output>

<gadget id="calculator">120 / 3</gadget>
<output>40</output>

<gadget id="calculator">40 * 2</gadget>
<output>80</output>

<result>80</result>