Two small electric cars A and B are placed on a toy circular bicycle lane with a circumference of 10 meters. The speed of A is 30 cm/s, and the speed of B is 20 cm/s. When they are 1 meter apart, they start at the same time. How many seconds have passed? A touch.
在一条周长10米的玩具环形单车道上放着两部小电动车A和B，A速度30厘米/秒，B速度20厘米/秒，当它们距离1米时同时开动，问经过多少秒第一次相碰．
<gadget id="calculator">30 - 20</gadget>
<output>10</output>

<gadget id="calculator">100 / 10</gadget>
<output>10</output>

<result>10</result>