There are two gears meshing with each other on the machine. The driving wheel has 100 teeth and rotates at 120 revolutions per minute. The driven wheel has 60 teeth, how many revolutions per minute? (Solution with proportional knowledge)
机器上有两个互相咬合的齿轮，主动轮有100个齿，每分转120转．从动轮有60个齿，每分转多少转？(用比例知识解)
<gadget id="calculator">120 * 100</gadget>
<output>12_000</output>

<gadget id="calculator">12_000 / 60</gadget>
<output>200</output>

<result>200</result>