The distance between AB and AB is 2000 km. Two cars, A and B, drive from the two cities of A and B at the same time. The speed of A is twice that of B. When A arrives at B, how many kilometers is B away from B?
AB两城相距2000千米．甲乙两辆汽车分别从AB两城同时相对开出，甲的速度是乙的两倍，当甲到达B城时，乙距B城还有多少千米．
<gadget id="calculator">2_000 / 2</gadget>
<output>1_000</output>

<gadget id="calculator">2_000 - 1_000</gadget>
<output>1_000</output>

<result>1_000</result>