一次環保知識競賽共有25道題,規定答對一道題得4分,答錯或不答一道題扣1分.在這次競賽中,小明被評為優秀(85...
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問題詳情:
一次環保知識競賽共有25道題,規定答對一道題得4分,答錯或不答一道題扣1分.在這次競賽中,小明被評為優秀(85分或85分以上),小明至少答對了幾道題?
【回答】
解:設小明答對了x道題,·············································································· 6分
4x-(25-x) ≥85····························································································· 8分
x≥22····························································································· 9分
所以,小明至少答對了22道題.····································································· 10分
知識點:不等式
題型:解答題