Xiaohua and Xiaoqiang went to Xinhua Bookstore and saw a copy of "Mathematical Stories". They both wanted to buy a copy, but they didn't have enough money. The difference between Xiaohua and Xiaoqiang was 7.2 yuan and 8.6 yuan. I can just buy a copy, how much is the price of "Mathematical Stories"?
小华和小强到新华书店看到了一本《数学故事》，他们都想买一本，可是他们带的钱都不够，小华差7.2元，小强差8.6元，如果把他俩的钱合起来刚好能买一本，《数学故事》的价钱是多少元？
<gadget id="calculator">7.2 + 8.6</gadget>
<output>15.8</output>

<result>15.8</result>