There are 285 willows, 15 more than three times the number of poplars. How many poplars are there? (column equations to solve problems)
柳树有285棵，比杨树的棵数的3倍还多15棵．杨树有多少棵？(列方程解决问题)
<gadget id="calculator">285 - 15</gadget>
<output>270</output>

<gadget id="calculator">270 / 3</gadget>
<output>90</output>

<result>90</result>