Xiaoya bought 2 bottles of correction fluid with the same price for 25 yuan, and the recovered money can just buy 4 packs of chewing gum with a unit price of 4.5 yuan. How much is the unit price of Xiaoya's correction fluid? (solution with equation)
小亚用25元买了2瓶价格相同的修正液，找回的钱正好可以买4包单价4.5元的口香糖，小亚买的修正液单价是多少元？(用方程解答)
<gadget id="calculator">4 * 4.5</gadget>
<output>18</output>

<gadget id="calculator">25 - 18</gadget>
<output>7</output>

<gadget id="calculator">7 / 2</gadget>
<output>7/2 = around 3.5</output>

<result>7/2 = around 3.5</result>