一次环保知识竞赛共有25道题，规定答对一道题得4分，答错或不答一道题扣1分.在这次竞赛中，小明被评为优秀（85...

问题详情：

一次环保知识竞赛共有25道题，规定答对一道题得4分，答错或不答一道题扣1分.在这次竞赛中，小明被评为优秀（85分或85分以上），小明至少答对了几道题？

【回答】

解：设小明答对了x道题，·············································································· 6分

4x－(25－x) ≥85····························································································· 8分

x≥22····························································································· 9分

所以，小明至少答对了22道题.····································································· 10分

知识点：不等式

题型：解答题