When Xiaohua, Xiaoli, and Xiaohong went to Xinhua Bookstore, they fell in love with the same book, but each of them did not have enough money to buy one of these books. It is known that the difference between Xiaohua is 0.65 yuan, that of Xiaoli is 0.5 yuan, and that of Xiaohong is 0.75 yuan. If you combine the money of the three of them, you can buy exactly two of these books. What is the unit price of this book?
小华、小丽、小红三人到新华书店时，看中了同一本书，但她们每人所带的钱都不够买一本这种书．已知小华差0.65元，小丽差0.5元，小红差0.75元．如果把她们三人的钱合起来，正好可以买2本这种书．这种书的单价是多少元．
<gadget id="calculator">0.65 + 0.5 + 0.75</gadget>
<output>1.9</output>

<gadget id="calculator">1 - 2</gadget>
<output>-1</output>

<gadget id="calculator">1 + 1 + (-1)</gadget>
<output>1</output>

<gadget id="calculator">1.9 / 1</gadget>
<output>1.9</output>

<result>1.9</result>