In order to build a happy city in a certain place, opinions were solicited extensively. 20% of the calls answered were construction calls, 10% traffic, 40% others, and 30% environmental protection. Among them, there were 60 construction calls. How many environmental protection phones are there?
某地为建设幸福城市，广泛征求意见，接听电话中建城占20%，交通占10%，其它占40%，环保占30%，其中建城电话有60个．环保电话有多少个？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">60 / (1/5)</gadget>
<output>300</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">300 * (3/10)</gadget>
<output>90</output>

<result>90</result>