The large gear has 40 teeth and the small gear has 24 teeth. If the big gear makes 90 revolutions per minute, how many revolutions per minute does the small gear make?
大齿轮有40个齿，小齿轮有24个齿．如果大齿轮每分转90圈，小齿轮每分转多少圈？
<gadget id="calculator">40 * 90</gadget>
<output>3_600</output>

<gadget id="calculator">3_600 / 24</gadget>
<output>150</output>

<result>150</result>