table, a chair and an iron are 540 yuan in total. It is known that the price of a chair is 60 yuan more than that of an iron, and the unit price of a table is twice that of a chair. How much is a chair, please?
一张桌子、一张椅子和一个熨斗共540元．已知一张椅子的价格比一个熨斗多60元，桌子单价是椅子的2倍．请问一张椅子多少元？
<gadget id="calculator">540 + 60</gadget>
<output>600</output>

<gadget id="calculator">2 + 1 + 1</gadget>
<output>4</output>

<gadget id="calculator">600 / 4</gadget>
<output>150</output>

<result>150</result>