Xiaoming bought a copy of "One Hundred Thousand Whys" for 8 yuan. The book Xiaohong bought was 3.5 yuan more expensive than Xiaoming. How much did Xiaohong spend on the book?
小明花8元买了一本《十万个为什么》，小红买的书比小明贵3.5元，小红买书花了多少元？
<gadget id="calculator">8 + 3.5</gadget>
<output>11.5</output>

<result>11.5</result>