A desk is 15 yuan more expensive than a chair. If the unit price of the chair is (2/5) the unit price of the desk, how much is the unit price of the desk? (column equation solution)
一张课桌比一张椅子贵15元，如果椅子的单价是课桌单价的(2/5)，课桌的单价是多少元？(列方程解答)
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">15 / (3/5)</gadget>
<output>25</output>

<result>25</result>