Two gears mesh together and rotate. The driving gear has 50 teeth and rotates at 100 revolutions per minute. The driven gear has 20 teeth. How many revolutions per minute? (Answer with proportional knowledge)
两个齿轮咬合在一起转动，主动齿轮有50个齿，每分钟转100转，从动齿轮有20个齿，每分钟转多少转？(用比例知识解答)
<gadget id="calculator">50 * 100</gadget>
<output>5_000</output>

<gadget id="calculator">5_000 / 20</gadget>
<output>250</output>

<result>250</result>