there were 100 adults and children .An adult could eat 3 buns while 3 children could only eat one bun,If 100 buns were finished,How many adults were there?
翻译：
成年人和儿童一共100人.一个成年人能吃3个小面包,3个儿童能吃一个小面包,如果一共吃了100小面包,那么有多少个成年人在那?
设成年人X个,儿童100-X个
3X + （100-X）x 1/3 = 100
解得：X=25
答：有25个成年人.（翻译：There were 25 adults）