Telecommunications workers install a batch of electric poles, 12 poles per day, and can be completed in 30 days. If they install 15 poles per day, it only takes a few days to complete the installation?
电讯工人装一批电杆，每天装12根，30天可以完成，如果每天装15根，只要几天就能装完？
<gadget id="calculator">30 / 15</gadget>
<output>2</output>

<gadget id="calculator">12 * 2</gadget>
<output>24</output>

<result>24</result>