A wire 60 cm long can go around a circular clock exactly twice. What is the circumference of the clock in cm?
一根长60厘米的铁丝正好可以绕圆形钟表两圈，这个钟表的周长是多少厘米．
<gadget id="calculator">60 / 2</gadget>
<output>30</output>

<result>30</result>