Haohao took 216 yuan to buy an Olympic commemorative book, and he just ran out of the money. After returning home, he did the math. If each commemorative book could be 1 yuan cheaper, then he could buy 3 more copies, and the money was just right. over. So, how much is the unit price of the album you bought?
浩浩拿了216元钱去买一种奥运纪念册，正好将钱用完，回家后他算了算，如果每本纪念册能便宜1元，那么他就可以多买3本，钱也正好用完．那么，那所买的纪念册的单价是多少元．
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